Lines drawn on a graph mean nothing. You guys need to stop wasting your time looking at graphs and look at the underlying fundamentals that drive those graphs. It's a social network and the commodity being bought and sold is attention and that means things like number of users, user activity, posts per day, etc.
When you see the 30 day average (new users per day), (posts per day), and things like that turn around, that is the time to by IMO. That will signify the bottom and a change in trend. Again, IMHO. :)