FYI, FireFox's "view source" doesn't show you the source that was sent, it appears to show you a reconstruction of the source based on what FireFox decided to render. Often the result is quite similar to the former, but the cases when it isn't are also usually the cases when you especially want to "view source" so it is a pretty lame misfeature that bit me several times before I learned to never trust FireFox's "view source".

Note that FireFox shows me the "Searches related to" stuff so my first guess is that your FireFox has a Google cookie that your IE does not, though I don't see an obvious user preference setting or such that would explain why a cookie would make such a difference.