They grab a lot of attention of the members here. I click signature links if it interests me. It brings a lot of sale many times.
Signature links are good for google and yahoo as backlinks. Basically if you and a competitor were tied down to about the same amount of links, then you could easily outrank them with having more signature links. So it's good for outranking some close competitors.
with any new sites i'm building, my first link is almost always from DP, along with the initial traffic (depending how webmaster related it is) some internal internal dp pages also have page rank, so it certainly wont do you any harm. I would say more valuable than the majority of directories
I believe signature ranks are good, but it really depends on the user. If the user is active, then yes, it could be beneficial to buy their signature space.
To a webmaster who wants more than a dozen or so daily hits, and they don't want a high bounce rate, if that, nope, not worth it. Not even close. For the clueless noobs, to the downright morons, probably worth it.
It is a decent way to build links for your personal site, but I wouldn't go so far as to buy them from other people.
I'd say back links from signatures do provide some weight, if not, they still can bring good traffic to your website.
represent what can help others is my motto. If you have a signature link make sure it has something to do with the forum its in. Think of relevant backlinks... In my time being a search engine consultant signature backlinks in a forum that your niche has to deal with definitely will out weigh nonsense in forums that your links have nothing to do with the content.
Sigs are valuable because you can get relevant anchor text to your website which will help you rankings
I see a lot of people mentioning "decent traffic" from signature links. Can someone quantify this? Exactly what is "decent traffic". I would love to have an idea of what kind of traffic I can expect from my sig.