Double-tapping and leaving your finger on the comment seems to bring up the magnifying glass on iOS 5, which will let you make a selection. If the grey box appears, its easiest if you let go of the screen and start the double-tap again.

I'm unsure what's causing the grey box, so I don't know if this is intentional, but for now it seems to be your best bet.

Double-tapping and leaving your finger on the comment seems to bring up the magnifying glass on iOS 5, which will let you make a selection. If the grey box appears, it's easiest if you let go of the screen and start the double-tap again.

I'm unsure what's causing the grey box, so I don't know if this is intentional, but for now it seems to be your best bet.