Someone once said that weblogs contain a gold mine of information about your users, and it’s true. Between your logs and software like Google Analytics, you can find out where your users IP addresses are located, what keywords they searched for to find your site, how they arrived on it, how long they stayed, how many pages they viewed, what kind of browser they used, and much more. However, these are all characteristics of your users. When it comes to finding out exactly who your users are, you’re generally out of luck.
But if a user is coming to your site by clicking on a link in Google Reader, it’s quite possible that you can find out who they are—sort of. I don’t often look at my own weblogs, but in doing so for the first time in months, I found something curious about visits coming from Google Reader. If you look at referring URLs from Google Reader, they should look similar to this: http://www.google.com/reader/view/user/05899714176177792238/ That number in there is a user id of the person from whose Google Reader account the visit originated. Take that number and put it into this URL and you’ll get that person’s shared items page, if they have one: http://www.google.com/reader/shared/05899714176177792238 (I intentionally made those numbers non-functioning in my examples.) Now, you’ll have a little more information: whatever public name the person has given herself and her shared items. Note that the number in these URLs is, apparently, different than the one use for public profile pages on Google. You people say you value privacy on the Internet, after all.