Here's a recent rant from search journalist, Danny Sullivan, regarding link spam. This is a good read for anyone involved with SEO.

"...the core problem is that the web has people who think nothing of vandalizing other web sites. That’s what link spamming is. You’re not adding value to a site. You’re simply spray painting garbage on someone else’s property, for your own personal benefit. You have no manners. You have no morals. You ought to be ashamed." - read more.

Community sites, such as discussion forums, social networking platforms, and blogs can use automated filters and human moderators to help combat spam but this does not fully deter spammers. Additionally, there are no federal or state laws (that i know of) against bombing someone else's website with irrelevant comments and threads in order to obtain a link for your own personal gain.

Other than moderating and software filtering, I wonder what other methods site owners use to combat link spam?

Link Spamming is really a serious problems for webmasters and today everyone is spamming forums, bookmarking sites to hell...

The only thing to do is to keep talking about it, and make link building schemes as a serious SEO deterent. Link builders have glorified their trade and even consider themselves search engine optimizers, even though many of them can't write English.

Web pages should never be rewarded for artificially gaining credible, relevant links, never. The search engine need to continue filtering this type of activity. They've done well by demeriting the dumpster directories and have come a long way with the link swappers but need to focus more attention on the useless blog commenting in order to drop links, nonsensial forum articles full of links, paid links, unworthy news articles in press releases, Linkedin spam (multiple profles linked together to appear important) etc.

I post my comment on Matt Cutts blog, the spam report pages, my blog, this forum, webmasterworld ... I get a lot of flack from the link schemers but somebody gotta' speak out.

Unfortunately, Google has made its riches off the back of the lolely link and it's going to take a long time to shake it off, unless the governments step in to clean it up. The Internet has become one big link dump.

Personally I'm surprised there aren't more sig link spamming "thanks for this informations!" posts in this thread yet.

yep! i agree with you, there should be an ethical way of putting in links, but i had to shutdown my blog (i had one blogger blog) and i removed a ll the no follow tags from it. in 7 days time my blog was full of 236 comments! i had to make it a no follow again, bu still they didnt stop coming. eventually i had to turn it off

That's a shame. One (arguably counter-productive) way of combating spam is blocking the IP address(es). Anyone have any experience with this?

the irony is that there are sites out there that offer ways to build one way backlinks without spamming, believe me I know as I spent 9 months developing one, but no matter how much you put it in peoples faces, they still get fixated with spamming blogs and directories.

People are mostly sheep unfortunately.

I think soon Google will take care of it in its own way. I think i feel how one big boom are coming for all link buyers,forum spamerrs and etc things - Nice dream yes?