I sort of found this by accident the other day. So far I love it. It’s called Smartr.
What does it do? It basically keeps track of every person you have ever emailed, all the people you are friends with on facebook and twitter. It builds a complete profile of each person with contact info, social media updates and message history. If you type in say like Michael it automatically sorts your list by contact frequency so the Michael’s (and there are a lot of them in New York) you talk to most come to the top of the heap.
You can email, place a call and SMS from inside the iphone app. Did I mention it’s free.
It also has a great gmail plug in that fits nicely over gmails ads and when you email someone you can put a name to the face and see their social status updates. It also recommends that you add people so you don’t leave a co-worker out the look (been there done that).
So far been using smartr for about a week and I love it. You should try it out fo youself.