Interesting study from Comscore about the behavior of users with regards to managing cookies on their computers. The data is presented in a somewhat convoluted manner, so let me highlight the key points:

1. On average a user clear cookies about 2.5 times a month on one computer.
2. While 69% of the users don’t clear cookies at all, 31% of the users clear cookies at least once every month on a computer.
3. 7% of the users are frequent cookie cutters, meaning that they clear cookies more than 4 time each month.
4. Looks like users clear cookies indiscriminately, without regard to the source of the cookie as the data is pretty similar for first party and third party cookies.

Overall, this data sounds about right as it jives well with data I got from a buddy of mine at Yahoo!. Some of the business implications of the data above are:

1. Cookie based tracking of the number of unique visitors is unreliable
2. Browser side cache for web pages can be unreliable as my guess is that when users clear their cookies, they also clear all the cached files (anybody has specific data here?) as they are considered same sort of private data…This means that a web site relying on browser side caching for scalability and performance of web site might be in for a surprise.
3. Cookie based tracking services like MyBlogLog etc. perhaps need a better way to track users? May be using browser plug-ins?

What do you think?