I just created an account last night and am having SO MUCH FUN with OSM! Last night I discovered new things about an old radio tower in my neighborhood, then used a browser plug-in called Apture to learn more about it without leaving the OSM page. Then used Archive.org to find some historical information that I then added to the notes field in the point on the map. So much fun!
I wrote about the experience and put in screenshots here http://marshallk.com/why-i-love-the-internet-so-much I highly recommend using the Apture browser plug-in along with OSM.
thanks everybody for making such a wonderful site, I'm really excited to participate in it!