On The Trail

As mentioned in the previous post two reports (1, 2) have found that about 1/2 of all users delete their cookies at least once a month. Why does this matter to an online marketer? Well, cookies are used in a variety of ways to measure the performance of online campaigns. If you’re trying to measure conversions for a particular campaign the user cookie allows you to tie together the initial clickthrough from the campaign with the conversion event (such as a purchase or an email newsletter signup or a white paper download). If the visitor doesn’t accept your cookie they’ll be counted as a clickthrough from that campaign, but they won’t be counted as a conversion, so your conversion rate will be artificially low.

Measuring deferred conversions (where the conversion occurs days or weeks after the initial clickthrough) is particularly hard if many of your visitors are deleting their cookies on a weekly or monthly basis. This number will be depressed even more than the immediate conversion rate since people who delete their cookies between clickthrough and conversion will not be counted. The “Lifetime Value” of a visitor is also affected since chances are good that their lifetime is less than a month.

Non-analytical marketing tools are also impacted by cookie deletion. Targeted content techniques often use cookies to determine what the user has viewed in the past. Most severely affected are banner ad and affiliate networks. They track people across multiple sites and set cookies from well known domains. Ad blocking and spyware blocking software target these cookies specifically. I suspect that the deletion rates for these cookies are higher than average.

There are the problems, what are the solutions? Tune in tomorrow for more…