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The Net Takeaway: More on "cookie killing"...


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More on "cookie killing"... · 05/03/2004 10:53 AM, Analysis

Eric Peterson wrote the book Web Analytics Demystified: A Marketers Guide to Understanding How Your Web Site Affects Your Business. He used to be with WebSideStory, and had earlier worked with Webtrends and Coremetrics. From reading his blog and parts of his book, he’s a pretty sharp character (and he hangs out with a good crowd)

He had a similar reaction to the recent reports of “perhaps 40% of users kill their cookies” that I did.

He questions the size of the numbers, and the lack of data around these broad claims. I agree that the numbers are probably wiggly, but I don’t really care: it doesn’t matter what the broad percentage is across the web, what matters is the specific group of people who visit your site.

I would point out that its a classic sampling problem. There are certain kinds of people who kill their cookies (or have friends or children who set up cookie killers on their machine for them). They are also more likely to be heavy users of the web. Doesn’t it stand to reason, therefore, that any broad “percentages” ignoring what segment the person resides in is useless? If I have 100% of my “heavy users” who kill their cookies, and 3% of my light users, then saying “40%” kill their cookie is rather silly.

Instead, measure it on your site. Do the same thing Redeye did: Link any identification system to the cookie placement, and segment your users by actions (initially). You will find that people who don’t get far past the home page may delete their cookie 100% of the time, but people who customize your site and register never do. NOW you can start talking about %ages… per groups of people with similar behaviors.

So, my post provided some potential strategies to work around cookie deleting, but again, the point is not that “people everywhere are rampantly killing cookies”. The questions to ask should be “I understand that some poeple do… but how bad is the problem on my site?” and “How important is it to me and my business to track them via cookies, or give them a reason to keep my cookie?”

Again, I don’t care what some broad research says about how the fruit salad of users kills their cookies. I want to treat my apples differently from my oranges.

(Ok, ps: An interesting approach would be to use the MediaMetrix/NielsenNetRatings panel, see how they deal with cookies, and segment them. Due to their weighting, you can start to tell how the “grey cloud of users” behaves in this regared. You can even match the segments up by how they behave on your site, if your site shows up in the behavioral panel tracking. But seriously, can we get past this?)

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  1. I was wondering about cookie deletion just the other day with regards to a site-logging problem.

    Michael, I see you use Textpattern for your blog. Maybe you know of a PHP cookie/session solution to accurate visitor tracking? I’d like to get a better handle on unique, new, etc. visitor counts.


    Jacob Patton
    JP    May 4, 10:45 AM    #

  2. I’ve taken the “shoemaker’s children” approach. While I analyze others’ logs all the time, I don’t take the time to work with my own.

    I have been playing with which I use here; it tells me how many visits accept cookies vs. those that don’t, though its reports are quick and not very deep.

    Also, I edit the DMOZ section about log file systems ( where I list some of the packages I’ve heard about. I try not to list counter-only systems there, but the counter systems will wind up being the winners in the long run, and I will probably add a section to cover them.

    For example, has some interesting capabilities.

    In general, you can use javascript or server-side programming to set both a perm and session cookie, and track whether the perm cookie is passed into your site on the first request (means user is a repeat visitor), if it is accepted and passed on the 2nd request (either 1st time visitor or deleter), and if it is rejected (cookie blocker).
    Michael Wexler    May 4, 02:45 PM    #

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