Hmm...this really is a tricky subject, guys - from both sides - so let me hop up on the fence and try to be as objective as possible.

As the owner of a web services company, I have spent lots of time and money doing everything possible to protect our site's look and feel. This is what j.becker referred to as "trade dress". Trade dress falls under trademark law, and very simply, is exceedingly difficult to protect. Don't assume the "look and feel" of your site is protected by copyright alone...it isn't.

But that also doesn't grant me the right to go copy-paste another site's template, tweak a few items, and call it inspiration. You have to be careful here. "Look and feel" doesn't rely on artwork alone, it encompasses the entire aesthetic. For instance, if the logos are removed, is it possible to say one site is definitively NOT related to the other? If there is any doubt, then you might have a case for trade dress infringement.

With that said, is it worth the trouble to cause trouble with the other service? Are you losing subscribers or money? This is where it gets tricky. Especially when there is a real trade dress issue. In this case (and I'm just being honest here), I see a clear trade dress issue on the frontpage at SMCars. Solution? There's no easy answer.

One might be for SMCars to credit CGCars for inspiring their frontpage design, or if both parties are willing, that SMCars is authorized to use the design, crediting ownership of the original concept to CGCars. Whatever the case, this should be a private conversation between site owners, not a public flame war. We are (mostly) adults here, and a little professionalism goes a long way in situations like these.

As a side note, CGCars will be connecting to our service in the coming weeks, and will appear on our banner at Internet Summit this November. My company is sponsoring Internet Summit, and plans to have ~100 communities and ~50,000,000 effective users connected before the end of the year. We are proud to have CGCars as a founding member, and welcome the possibility of connecting SMCars as well.

I hope this helps. I hate to see any community suffer over an issue like this. CGCars has a very unique look and feel. SMCars (at the moment) is slightly less unique imo, but are obviously making an effort to define their space and create a unique environment. I would urge the owners to connect and figure this out. If you like, I would be happy to join the conversation.

Nate