AN OVERBROAD PATENT ON Determining whether or not features of discussion thread pages have changed with time - This application from Sony seeks to patent the idea of...Recording contents of an electronic page at different intervals and determining changes in the contents! 10 minutes of your time can help narrow US patent applications before they become patents. Follow @askpatents on twitter to help.

QUESTION - Have you seen anything that was published before 7/26/2011 that discusses:

  • Determining change in contents of a discussion thread page with time.

If so, please submit evidence of prior art as an answer to this question. We welcome multiple answers from the same individual.

EXTRA CREDIT - An electronic bulletin board system: includes discussion thread pages each associated with a discussion topic, allows a user to create a new discussion thread page for a new discussion topic, or post a comment to an already created discussion thread page.

TITLE: Determining changes in contents of a discussion thread with time.

Summary: [Translated from Legalese into English] Identifying contents of a page at various time intervals, and determining whether a feature of the page has changed based on the content.

  • Publication Number: US 20130031118 A1
  • Application Number: US 13/554,135
  • Assignee: Sony
  • Prior Art Date: Seeking prior Art predating 7/26/2011
  • Link to Google Prior Art Search - "Find Prior Art"

Claim 1 requires each and every step below:

An information processing system, comprising:

  1. An identifying unit that repeatedly identifies a content of a page whose content changes with a lapse of time; and

  2. A determination unit that determines based on contents of the page identified at different timings whether or not a feature of the identified page has changed.

In English this means:

An information processing system for:

  1. identifying contents of a page whose contents changes with time, at various time intervals; and

  2. determining whether a feature of the page has changed on the basis of the identified contents of the page at the various time intervals.

Good prior art would be evidence of a system that did each and every one of these steps prior to 7/26/2011

You're probably aware of ten pieces of art that meet this criteria already... separately, the applicant is claiming Receiving a search request and searching discussion thread pages matching the received search request.

"Identify change in contents of a discussion thread" from the Applicant

What is good prior art? Please see our FAQ.

Want to help? Please vote or comment on submissions below. We welcome you to post your own request for prior art on other questionable US Patent Applications.

  • 1
    So if I understand this, it wants to do a comparison of two search results for the same thread done at different times such that it can say this is a hot thread or an active thread.
    – Elin
    Jan 15, 2014 at 2:24

2 Answers 2


The need to determine if page content has changed is commonly associated with cache busting or clearing a cached page based on changes which have been made to it. Because of how common this particular problem is, techniques readily exist to determine if changes have been made to any page and even partial pages (comment threads, etc.). I've written them myself for certain projects but I'll link to some which are easy to find online.

Generational Caching is a means of keeping track of any object or piece of data as it is modified over time. This is generic to basically anything which could be stored in a database, including the individual comments of a comment thread and even the comment thread itself. A comment looks like anything else in a database. It's just data. So specifying that this solution addresses comment threads doesn't make it novel. Even if it were novel because of that, here are some Drupal developers solving the same problem in 2005 specifically for comment threads. They are caching comment threads and then analyzing the threads to determine if a change has occurred.

Also, this Stackoverflow discussion specifically shows a user (Nixarn) attempting to solve a caching issue in which it is necessary to determine if a comment thread has been modified. To solve his issue, he will have to determine if the comments have changed over time. Other users recommend ready-made solutions including an open source package called Django-groupcache which was created in April of 2011.

Finally, here is an open source command posted on commandlinefu.com by user, "Emzy" in 2010 which does exactly what this patent application claims to be novel and unobvious. The user recommends putting this command "in a cron" which simply means to set the script up to be run automatically at a specified interval. The command makes use of "diff" which is part of the GNU toolset "diffutils".

In short, this command will store the contents of a webpage (including any comments sections which may exist) and compare it with future versions of the same piece of information. If there is a difference, it will even email you to let you know that it's changed. It does all of this in two lines of code.

This may be one of the most solved problems available to humanity in this day and age. Diff is used extensively to find changes within text-based and even binary data and has been around since the 70's. My guess is that ~90% of web applications employ some type of automated cache-clearing solution where they monitor the changes being made to various types of objects (including objects representing comments). They would all infringe on this patent the day it was approved because they've been doing it for years.

  • This patent is not about content change and caching. It checks for content changes and then looks to see if the content change causes a feature change. If so, the feature is updated. The example given is "hot topics". Presumably a change in the content of a thread could cause one thread to take the place of another thread on a "top ten threads" list.
    – George White
    Jan 16, 2014 at 21:10
  • I've been thinking that "analyzing content" and "detection of a change in a feature of a page" means more than "take a diff" although a diff is possibly part of it. I think they are saying that they can generate something like "Hot Network Questions" without being able to directly query the SE database for the dates/times/frequency of comments. They are an external entity trying to create that list based just on the rendered pages.
    – Elin
    Jan 17, 2014 at 1:18
  • Reading the claims, I really wonder if they are saying they only want to know if there are new comments, not if there is any other change to either the existing comments or the post starting the thread.
    – Elin
    Jan 18, 2014 at 20:40

Here's an example from 2006 of changing the 'hotness' of a returned item over time based on updates to that item and adjusting search engine results accordingly:

A search engine has a query server (50) arranged to receive a search query from a user and return search results, the query server being arranged to identify one or more of the content items relevant to the query, to access a record of changes over time of occurrences of the identified content items, and rank the search results according to the record of changes. TMs can help find those content items which are currently active, and to track or compare the popularity of content items. This is particularly useful for content items whose subjective value to the user depends on them being topical or fashionable. A content analyzer (100) creates a fingerprint database of fingerprints, to compare the fingerprints to determine a number of occurrences of a given content item at a given time, and to record the changes over time of the occurrences.

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