Beside size, signature content should not contain the following materials:-
All Types
Commercial advertising (except links to threads in the Trade Zone)
Referral link for commercial purposes.
Links directing to illegal and objectable materials (warez, cracks, pornography, pyramid schemes, referral ID's)
Links of a malicious nature. e.g. those that crash your browser, trigger popup floods or emulate BSOD's
Flaming/Insults of another member
Political statements
Religious statements
Spoiler tags