Patent Application
20110288940
The invention relates to user tracking in online services. More specifically, the invention relates to techniques for improving the accuracy of cookie-based tracking schemes.
Those who deliver products or services (or, more generally, information) over the Internet have a strong interest—financially and otherwise—in tracking and analyzing visitors, visits, page views, browsing histories and other characteristics of their customers. For example, a publisher may provide a content site and wish to analyze the reach and frequency of advertising delivered to individual visitors. To do this they must have a reliable and long-lasting way to recognize repeat visitors. Providers of digital products or services primarily use HTTP cookies as a tracking mechanism to determine whether the current visitor is the same visitor that was seen before, or is a new visitor. (HTTP cookies are described in detail in Internet Engineering Task Force (“IETF”) Request for Comments (“RFC”) documents RFC2965, published October 2000.) A publisher's web infrastructure may build up a significant amount of interesting information about a visitor over the course of his many page views. This information is tracked and correlated to that visitor by the means of a cookie issued to the visitor's device. A publisher gets great value from the information it is able to collect about visitors—for example, in estimating user counts, or in selling advertisements to a targeted market, and so on—and thus there is considerable value in being able to build a lasting record of a visitor.
Unfortunately, cookies are easily and often deleted. When this happens, all of the collected information about a visitor may be lost. After cookie deletion, a new cookie will be issued to that visitor on his next visit, and the process of collecting information starts again. The system no longer has any way to know that the current visitor is the same as the previous visitor, because the original cookie was deleted. Any analysis system relying on cookies may mistakenly believe that there are two different visitors (one from before the cookie deletion, and a new visitor after the cookie deletion)—when in fact these are the same visitor. This causes errors in analysis—for example in this case an analytics system would report two unique users, when in fact there was only one. Significantly increased accuracy of analysis would be achieved if the system were able to “stitch together” those two cookies and understand that they both represent the same visitor.
Embodiments of the invention correlate multiple unique cookies as having originated from the same device using device fingerprinting. The general method is to collect and record characteristics of a device (the “device fingerprint”) that, taken together, may uniquely identify the device, or at least narrow the set of possible devices from which the fingerprint could have come. The fingerprint is used when a cookie is issued or referenced, and then later to compare the device fingerprint when cookies are analyzed to determine if those cookies were originally issued to the same device. By “stitching together” unique cookies that were issued to the same device, and conflating them to a single virtual cookie, analytics and other systems that make use of cookies to identify users or devices can produce much more accurate results.
Embodiments of the invention are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean “at least one.”
Embodiments of the present invention are believed to be superior to prior-art cookie-based content-tracking systems for several reasons, including:
One embodiment of our invention involves the analysis of users of Internet-based web publication using HTTP cookies.
Web server 130 also interacts with an analysis server 160 which (in the environment depicted here) is executing on another computer 170. A database 180 is provided for storing information used by analysis server 160 to perform its role in the operations detailed below.
At 210, a browser sends a request to a web server to cause the server to provide information. If this is the first request from the browser to the server, the request will not include a cookie. The server receives the request and prepares an appropriate response (220). If the request does not include a cookie (230), then a “Set-Cookie” header will be added to the response (250). The response is sent back to the browser (260) and presented to the user (270). The user may cause the browser to make another request for information (280). This request (and subsequent requests) will include the cookie, so the server will skip step 250 in preparing subsequent responses.
However, on occasion, the browser's cookie may be cleared or deleted (290), so a subsequent request is again made without a cookie (210), and the server will prepare a response (220) including a new Set-Cookie header (250).
A web server operating according to known, prior-art HTTP state-maintenance protocols (e.g., cookies) may be unable to distinguish between two series of requests from two different browsers that have never visited the server before, and a single series of requests from one browser, where the single series of requests is interrupted by a cookie-clearing event.
Next, the browser transmits the cookie and device information to the web server (340). The web server forwards the fingerprint data, and other information about the HTTP request (such as the HTTP headers and source IP address) to an analysis server (350). The analysis server stores the information for future use (360) and may reply to the web server that the browser has not been seen previously (370).
Subsequent requests from the browser proceed as usual: the browser sends its assigned cookie, and the web server can correlate these requests with previous requests, collecting information of interest to the publisher about the resources the browser references. The web server may continue to transmit fingerprint-data collection code, and changes to the device's fingerprint can be detected and monitored. For example, the user may install a new display device, so the device fingerprint might show a different screen resolution or color depth. All this information can be kept exclusively within the web server, or shared with the analysis server.
The information available to the analysis server in the device fingerprint and HTTP headers may include some or all of the following data:
It is appreciated that the dynamic pattern of interaction between a browser and a web server also yields identifying information, and, to the extent that this information is captured and stored, it may be available to the analysis server to assist in identifying a client without a cookie, or with a newly-assigned cookie, as a previously-seen client whose old cookie was associated with an earlier browsing history. Thus, in some embodiments, the determination that a client with a newly-initialized browsing history is actually the same as an earlier client may be emergent, developing over a series of browsing interactions. Roughly speaking, the bare fingerprint data may suggest that a “new” client is the same as an earlier client, but continued browsing activity may provide an increased level of confidence in the identification. Alternatively, continued browsing may show that the browser tentatively identified as the same as an earlier client based on the fingerprint data, is in fact more likely to be a new client after all.
Embodiments of the invention may incorporate a number of variants to accomplish the goal of correlating multiple series of web interactions:
Other alternate embodiments include:
An embodiment of the invention may be a machine-readable medium having stored thereon data and instructions to cause a programmable processor to perform operations as described above. In other embodiments, the operations might be performed by specific hardware components that contain hardwired logic. Those operations might alternatively be performed by any combination of programmed computer components and custom hardware components.
Instructions for a programmable processor may be stored in a form that is directly executable by the processor (“object” or “executable” form), or the instructions may be stored in a human-readable text form called “source code” that can be automatically processed by a development tool commonly known as a “compiler” to produce executable code. Instructions may also be specified as a difference or “delta” from a predetermined version of a basic source code. The delta (also called a “patch”) can be used to prepare instructions to implement an embodiment of the invention, starting with a commonly-available source code package that does not contain an embodiment.
In some embodiments, the instructions for a programmable processor may be treated as data and used to modulate a carrier signal, which can subsequently be sent to a remote receiver, where the signal is demodulated to recover the instructions, and the instructions are executed to implement the methods of an embodiment at the remote receiver. In the vernacular, such modulation and transmission are known as “serving” the instructions, while receiving and demodulating are often called “downloading.” In other words, one embodiment “serves” (i.e., encodes and sends) the instructions of an embodiment to a client, often over a distributed data network like the Internet. The instructions thus transmitted can be saved on a hard disk or other data storage device at the receiver to create another embodiment of the invention, meeting the description of a machine-readable medium storing data and instructions to perform some of the operations discussed above. Compiling (if necessary) and executing such an embodiment at the receiver may result in the receiver performing operations according to a third embodiment.
In the preceding description, numerous details were set forth. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without some of these specific details. In some instances, well-known structures and devices are shown in block diagram form, rather than in detail, in order to avoid obscuring the present invention.
Some portions of the detailed descriptions may have been presented in terms of algorithms and symbolic representations of operations on data bits within a computer memory. These algorithmic descriptions and representations are the means used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art. An algorithm is here, and generally, conceived to be a self-consistent sequence of steps leading to a desired result. The steps are those requiring physical manipulations of physical quantities. Usually, though not necessarily, these quantities take the form of electrical or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated. It has proven convenient at times, principally for reasons of common usage, to refer to these signals as bits, values, elements, symbols, characters, terms, numbers, or the like.
It should be borne in mind, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. Unless specifically stated otherwise as apparent from the preceding discussion, it is appreciated that throughout the description, discussions utilizing terms such as “processing” or “computing” or “calculating” or “determining” or “displaying” or the like, refer to the action and processes of a computer system or similar electronic computing device, that manipulates and transforms data represented as physical (electronic) quantities within the computer system's registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage, transmission or display devices.
The present invention also relates to apparatus for performing the operations herein. This apparatus may be specially constructed for the required purposes, or it may comprise a general purpose computer selectively activated or reconfigured by a computer program stored in the computer. Such a computer program may be stored in a computer readable storage medium, including without limitation any type of disk including floppy disks, optical disks, compact disc read-only memory (“CD-ROM”), and magnetic-optical disks, read-only memories (ROMs), random access memories (RAMs), erasable, programmable read-only memories (“EPROMs”), electrically-erasable read-only memories (“EEPROMs”), magnetic or optical cards, or any type of media suitable for storing computer instructions.
The algorithms and displays presented herein are not inherently related to any particular computer or other apparatus. Various general purpose systems may be used with programs in accordance with the teachings herein, or it may prove convenient to construct more specialized apparatus to perform the required method steps. The required structure for a variety of these systems will be recited in the claims below. In addition, the present invention is not described with reference to any particular programming language. It will be appreciated that a variety of programming languages may be used to implement the teachings of the invention as described herein.
The applications of the present invention have been described largely by reference to specific examples and in terms of particular allocations of functionality to certain hardware and/or software components. However, those of skill in the art will recognize that client correlation based on device fingerprints can also be produced by software and hardware that distribute the functions of embodiments of this invention differently than herein described. Such variations and implementations are understood to be captured according to the following claims.
This application claims the benefit of U.S. provisional patent application No. 61/347,734, filed 24 May 2010.
| Number | Date | Country | |
|---|---|---|---|
| 61347734 | May 2010 | US |
