Jupiter Research published a solid report on cookies today - see this press release.
99+% of commercial sites require user to have cookies turned on for making a purchase, such cookies are typically session-based and expire automatically after 30 minutes or so. Another type of cookies, called persistent cookies, are stored for a longer period of time and are used to identify returning users. If you’ve been to a site recently and have seen the message “welcome back Paul” without login to the site, it is probably because a persistent cookie was set on your computer.
Jupiter polled thousands of end users on cookie usage and the results are appalling: up to 40% of users delete all their cookies on a regular basis, as often as weekly or monthly. The consequences are significant for a number of applications: personalization, Web analytics, advertising, etc. If persistent cookies are deleted we cannot accurately track users over multiple sessions for long periods of time. We cannot target anonymous users based on past behavior on the site. We cannot deliver ads which are more relevant and targeted. Everyone’s Joe Blow.
For Web analytics, a few questions arise (assuming this research is reliable). If 40% of users frequently delete their cookies it means Marketers are underestimating all deferred conversions resulting from older marketing campaigns. They are also overestimating the number of new prospects (or first time users) who are visiting, since some of them might be returning users who cleared their cookies.
Arguably the research is seriously denting any hopes of using the Web to track individual users for long periods of time. Lifetime value can still be measured down to individual users, but it’s getting harder and harder to know how users are behaving between 2 purchases: what products they looked at, how many visits before a purchase, initial entry point to the site, etc. Many of us analytics experts have dreamed of using individual click-stream patterns to drive more personalized, relevant marketing campaigns, at the right time. “If user X has visited the DVD section of the site 3 times in the last 12 weeks, send him an email with a coupon”.
On the other hand maybe it is time for all of us to acknowledge how perishable and fragile Web data is.
- Perishable since most modern sites update their site and content at least every 2 weeks, since product selection constantly changes, since marketing campaigns are short, extremely seasonal and extremely dynamic. As an example, does it make sense to run a home page path analysis query for December 18th today March 10th? Are you hoping to find out something interesting?
- Fragile since data collection and accuracy issues have been present in the Web analytics space since day 1. Whatever the technologies (logs, ASP, in-house), it is hard to get a real accurate assessment of online activity. Period.
So if we look back at today’s announcement, yes we are learning that maybe our returning users reports aren’t as accurate. But the damage is relatively contained and we should be able to work around this. For example, think of marketing campaigns. Most of my customers track their campaigns down to individual users within 7 days of the initial entry, no more. Deferred campaign data will be off, but not by much since few people delete their cookies every week, according to the research.
Overall, this research will inevitably influence the future of Analytics. But if it forces us to better understand and use Web analytics data, this could in the end be a good thing.