Interesting question JTA10,
In my opinion it could either be useful for a brand or it could be detrimental. On the one hand, its unique, people will remember it and if you are in business in a niche that has to do with internet marketing, you would look like you were on the cutting edge.
On the other hand, you miss out on the trust that people place in the more common TLD's, especially if you are in a niche where the customer base may be more sensitive to non-traditional TLD's. I would be interested to hear how it works out for you.
Best,
Shawn