update : The weight graph and many other graphs are now avaiable in the Measurement Tracker -- if you want to see your weight graph go there, not in the upper right hand corner :)

There is a new feature that will graph your weight change. The graph will appear in the upper right hand corner of the web page.

(note you need to be signed into your account to see this graph. If you do not have an account you can get a free one here)