EDIT: I hit my HN rate limit for the morning, so my response to your comment below follows:
AppleInsider is extremely unlikely to be confused with an Apple website, however. Particularly since it's style is very different, and a "news and rumors" site about Apple isn't likely to be confused for an Apple site. (And as a sidebar, even if Apple did want to C&D them, they'd have a much harder time C&Ding a journalistic presence.)
In the case of yours, I had to check the copyright fine print to determine it was not a Google website.
Even changing the logo and site design from the standard Google corporate style would help.
What you've done is the equivalent of saying "DISCLAIMER: I DO NOT OWN THIS VIDEO" on a youtube video of a tv show. Just because you're saying you don't own it and your intentions (may be/are) good does not mean the holder of the trademark or copyright will just say 'oh he seems nice, let him keep it up'.
(note the update)
You have a much more difficult defense in that you've produced something that does what the layperson associates Google with: search. Even worse, you are using Google's name and logo. It's been awhile since I've read through Google's TOS, but generally, TOS are very explicit about not using their trademark name or logo in such a way that implies endorsement.
I'm sorry for any confusion I may have caused in making you think it was a service of Google's. I viewed it as a tribute to one of my favorite services of theirs (custom search engines) and let that cloud my legal perspective.
Anyway, I didn't hear from Google, but also didn't want them to have to engage their legal team, so I went ahead and rebranded today.
Lesson learned, and thanks again everyone for the great feedback yesterday.