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January 9th, 2006

AWStats - How is the Add To Favorites (Estimated) Feature Calculated?

Quick Answer:
A quote from the AWStats glossary:

Add To Favourites:
This value, available in the “miscellanous chart”, reports an estimated indicator that can be used to have an idea of the number of times a visitor has added your web site into its favourite bookmarks.
The technical rules for that is the following formula:
Number of Add to Favourites = round((x+y) / r)
where
x = Number of hits made by IE browsers for “/anydir/favicon.ico”, with a referer field not defined, and with no 404 error code
y = Number of hits made by IE browsers for “/favicon.ico”, with a referer field not defined, with or without 404 error code
r = Ratio of hits made by IE browsers compared to hits made by all browsers (r <= 1)

As you can see in formula, only IE is used to count reliable "add", the "Add to favourites" for other browsers are estimated using ratio of other browsers usage compared to ratio of IE usage. The reason is that only IE do a hit on favicon.ico nearly ONLY when a user add the page to its favourites. The other browsers make often hits on this file also for other reasons so we can't count one "hit" as one "add" since it might be a hit for another reason.
AWStats differentiate also hits with error and not to avoid counting multiple hits made recursively in upper path when favicon.ico file is not found in deeper directory of path.
Note that this number is just an indicator that is in most case higher than true value. The reason is that even IE browser sometimes make hit on favicon without an "Add to favourites" action by a user.


What am I talking about?

AWStats is a free website traffic analyizer that I use to look at who comes here and why. It has a section shown below that claims to tell me who has bookmarked my site:
AWstats

And I was just curious how on earth they can know that.

Anyway now you have your answer, and here are the searches I did that indirectly got me to the glossary eventually:

  1. “Add to favorites (estimated)” how does it work?
  2. Add to favorites (estimated) how does it work?

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Posted by Greg Pinero (Primary Searcher) in WordPress, Other

This entry was posted on Monday, January 9th, 2006 at 8:05 pm and is filed under WordPress, Other. You can follow any responses to this entry through the comments RSS 2.0 feed. Both comments and pings are currently closed.

6 Responses to “AWStats - How is the Add To Favorites (Estimated) Feature Calculated?”

  1. Dave P says:

    Nicely done. Obviously, I was wondering the same thing myself, which is why I’m here!

    Neat idea for a website! Thanks for the answer!

  2. Ben Hutchings says:

    Yep me too.. so now that I know that its based on IE grabbing the favicon, it means that this stat will become almost useless when IE 7 goes on general release. It does exactly what the other browsers do now and grabs for a favicon.ico on most if not all visits so that it can display it in the address bar.
    So… I guess my advice would be, don’t rely on this stat anymore!

  3. Greg Pinero (Primary Searcher) says:

    Ben,

    That sounds like good advice. It’s a shame too because as a concept, bookmarking is an extremely useful metric.

  4. Eirik says:

    nice going! Add to favorites (estimated) 510 / 678 Visitors 75.2 %… on my website

    seems a little high

  5. jintu says:

    was wondering too about this. my record shows 18/20 and it is only a couple of days since I changed host. can anybody explain this phenom furthers. Thanks

  6. Jintu says:

    I got this today:

    Add to favorites (estimated) 35 / 31 Visitors 112.9 %

    I’m confused could somebody explain this? Thanks