Well... hopefully this problem will go away once and for all now.
The new software allows for users to show or hide other people's signatures, so if you don't want to see them, you can turn them off. (Option is in your profile)
If you do have them switched on, the size on screen is limited to a maximum amount.. if a member has a big signature, a scroll bar will appear on the right hand side so you can choose to look at the whole thing if you wish !
;D