The banner ads at the top take a few moments to load after the page has loaded, so by the time I click a link the screen moves down and I end up clicking some other random thing. Irksome.
Also sending pms - after clicking send it gives no indication that it's been sent. I have just realised I sent someone about 5 of the same pm the other day because the button didn't seem to be doing anything 
I'm on an Android phone but have had similar issues with a newish android tablet.