We're all things to all people.
Seriously though - USP is a buzz word that's over used. It doesn't have a place in all businesses, and trying to emphasise a USP when you don't really have one can look more than a little tacky. The reality is that most businesses don't have a USP, and most of them get by just fine.
We were having a discussion in the office today about our own USP (the phrase was never used - we were talking about what made us different to our competitors), and the conclusion we came to was that we had no way of knowing if our emphases of this aspect of our business was really benefiting us. All we did know for sure was that it was costing us huge man hours. The plan for next year is to 'phase out' our USP and see if it makes a difference to our customers - because if it doesn't, it will save us a huge wage bill.
My opinion is that in a few years this phrase will go the way of all buzz words - it won't be used anymore, and businesses will go back to trying to stand out from the crowd. Which amounts to the same thing.
Does anyone still talk about elevator speeches? This was all the rage a couple of years ago - everyone had to have one. And blogs - a couple of years ago every business was talking about how they needed to get blogging. Now, the only businesses who blog are those that genuinely benefit from it.
Ditto Twitter, Facebook, etc.