In the vein of
http://news.ycombinator.com/item?id=43967471. It looks like a nice professional design so it does not give off initial bad vibes
2. The first thing that appears after login is a pop up asking me to get other people to join. I thought this was how to thank people at first. I think this is an unecessary pop up - this is a viral idea anyway, you dont need people to pre-join - the "thank" message will do that for you, so drop that first pop up - very confusing
3. I had to hunt around till I found how to thank people. I would put a different UX up front - in fact that pop up was fine - it had about 30 of my friends, just let me click one.
4. the search box is fine but I am moslty going to thank friends first surely.
5. add it to linkedin - will be a great networking add on
6. I want to send a message with the thank, and preview it. I still dontknow what I just sent. THat would worry me
Overall, yeah nice but its not a good home for Facebook. Put it on linkedin, and I see it, on facebook, no. But that might just be me
goodluck