I've been using StackOverflow for over a year now and I still don't know how to fully interpret the reputation history graphs. Can we get more help on what is being displayed and probably more information about why we got upvoted, downvoted, and for what message, comments, etc?
http://stackoverflow.com/reputation for Stack Overflow
Basic format is as follows:
VT PN (rep)
VT = Vote type - 1 = Accept, 2 = Upvoted, 3 = Downvote(d) (depends on number in (rep))