"....
There’s four things of note here.
Firstly it’s on Google’s domain, not some other domain like Google Gadgets or something. So yes, it’s bad for phishing and for cookies.
Secondly, it’s over SSL/TLS (so no one should be able to see what’s going on, right?).
Third, it could be used to hijack Google Buzz – as if anyone is using that product (or at least you shouldn’t be).
And lastly isn’t it ironic that Google is asking to know where I am on the very same page that’s being compromised?
...."

http://ha.ckers.org/blog/20100216/google-buzz-security-flaw/

The vulnerability has been fixed now:

http://www.computerworld.com/s/article/9158218/Google_fixes_Buzz_bug