Wooow, it looks really funky on my phone.. Some posts look fine (top one in screenshot), and random posts have the messed up sig, plus the text of the post is reaally small...
The palm pre runs webkit, as does chrome, safari, etc.. Maybe that's what's causing it?
Browser info:
Mozilla/5.0 (webOS/1.3.1; U; en-US) AppleWebKit/525.27.1 (KHTML, like Gecko) Version/1.0 Safari/525.27.1 Pre/1.0