Google API terms
If you're using a Google API with your weblog system, like the MTGoogleSearch tags for Movable Type or google.macros.box for Radio Userland, you might wish to re-read this section of the Google Web APIs Terms of Service:
And you may not use the search results provided by the Google Web APIs service with an existing product or service that competes with products or services offered by Google.
It's probably worth considering whether you're in danger of violating the terms. Most likely, you're not, as you'd have to offer weblogging services of your own that used the Google API to compete with Blogger, but it's certainly something that seems like it could raise an issue for how these APIs are implemented.