I always had an issue w/ signatures taking away from the thread's relevant information when reading 50-60 pages of posts, and seeing nothing but a bunch of self expression vs. participation in the debate.
I got to the point for 2-3 years of all that mess shoved in the member profile (where it belongs) and disabled signatures.
This allowed me to re-enable signatures.
Tralala,
There is less HTML to process per page of threads by the client browser, hence the page will load faster and "lag" less when scrolling up and down as there are less objects per page load.
(anyway my system lags less w/ my normal 20-30 windows open and 15 programs running)