Personalized search and personalized home pages can be great for most users. The only issue is that you need to be signed in, most of the time, to get personalized results from Google. And if you love those personalized results and home page from iGoogle, being automatically signed out without requesting to be signed out, can be a bit frustrating.
Over the past week, I have seen dozens of threads pop out in several Google forums on the topic of Google automatically signing them out of iGoogle. I ignored it as being a recent security patch that deleted cookies and thought it would be resolved soon.
Google recently posted an announcement on this exact issue, saying:
Several users have reported that they're getting signed out of iGoogle several times each day. This is not the way it's supposed to work, and we're investigating the issue on our end.
If you're affected by this problem, please first check to make sure this isn't a problem with your computer or network; instructions for checking are located in this Help Center article. Once you've eliminated those possibilities, if you'd like to discuss this further please post in this thread.
So if you are also being signed out from Google, don't feel left alone.
Forum discussion at Google Web Search Help.