It is funny how many of the forums in the SEM community start the same types of threads even thought they are not brought up on time sensitive industry news. For example, there are three forums (that I know of) that have new threads on what is or is not allowed in the signature file of their member's profile. I thought it would be a good idea to summarize which forums allow what at this current time:
Do Not Allow Signatures: WebmasterWorld also does not allow signature files.
JimWorld is an other forum that does not allow for signature lines.
SearchEngineWatch does not allow signatures. Instead they recommend that the users customize the text that appears under your member name.
Do Allow Signatures: Cre8asite Forums allows for 2 or 3 lines in the signature file and allow links do not distribute link popularity.
HighRankings does allow for 2 links within the signature lines.
ABAKUS Forum also allows for signature lines.
Webmaster Forum allows for signature files.
IHelpYou Forums allows for signatures.
SitePoint Forums allows for signatures.
WebProWorld allows for signatures.
SEO Guy's Forum allows for signatures.
DigitalPoints Forum allows for signatures.