[ig1]

Here's a simple rule: Don't use someone-else's trademark as the fist word of your product name.

The first word is typically used to imply endorsement or officialness. So for example Microsoft X or Google Y.

If you build a product based on a third party service, you can generally use the trademark in your name for example "Bob's invites to Google+", as long as it's clear it's not an officially produced or endorsed product.

[robryan]

With Google though you would ideally want to avoid it altogether, although in this case that wouldn't really be possible. A lot of Google logos have specific terms of use, most of which include that they can't be modified in any way which I thinking might have resulted in the ban in this case.