Does Google "ban" a website if we use signature on many websites with the address of our website ? my website disapeared in search for my name ( is in 550... position ) , the same was with the proxy site , i removed signature and is back ...
You have placed your website link in your signature only for the purpose of getting links, getting traffic and google can crawl fast your website. But, Google can't crawl your signature link every time. Google crawl your link on weekly basis period. And for signature link i don't think that Google can penalize your website.
When you'll put up a sig in forums, the anchor text should be your target keywords (in your case, the anchor text is too long)
Do you realize that, if they would give out ban to sites for that, this could be easiest way to drown all your competitors? This is to simple.
I'm sure your drop in SERPs had nothing to do with your signature links...unless you removed all of them for an extended period of time.
google tend to have negative opinion about some words like buy links, buy text ads, selling links. did you use any of those in your signiture? try changing them to something else.