I have been playing with Forum Sig links for a few months now & tested a theory over the course of the last 2 months. Simply put, I took 3 accounts on separate forums with one sig link (around 1,800+ total posts combined) & added a 2nd Sig link to all 3 forum accounts. with 48 hrs. ALL IBLS for Google / Yahoo / MSN dropped to "0" While Both AlltheWeb & AltaVista climbed to 1,800+ IBL's. The top 3 engines sat at "0" for about 1 1/2 weeks & then slowly started to clime again, within 3 weeks Yahoo & MSN matched AlltheWeb & AltaVista & Google returned to its normal stance. To make sure this wasn't an Isolated incident, I repeated the process by removing 1 sig link & replacing it with another one on all the same forum accounts. Low & Behold, the same thing happened with the exception that it took 4 weeks this time to level back out in the top 3 engines. because of this I would have to firmly say that MASS IBL's DO generate a RedFlag in the more enhanced Algorithms (Namely Google / Yahoo / MSN) & cause a 3-4 week penalty for suspected Spam. Their may be cases with longer blackout times than mine, however, the results that I found was enough for me to start slowly building Vs. mass submissions. No telling what a more Spammy approach other than forum sigs would have done to me (E.G. Link Farms, FFA's, Web Rings, Mass Directories, Etc.). This is one of those better safe than sorry reality checks for me... Any of you have similar research? Anyways, I thought I would share my experiences so that others can at least be aware of the possibilities..