This is an issue that directly effects me because I own a tablature site. A lot of you probably know that recently some big name sites like guitarzone.com and mxtabs.net (though this one is coming back this summer. yay.) have been shut down by the RIAA on the basis that distributing guitar tabs online is copyright infringement. Personally I don't think guitar tabs should be viewed like this. They are primarily a very effective learning tool for beginning guitarists. They are an important resource for students. The fact that kids can get free tabs online I think doesn't hurt songwriters at all because most tabs are inaccurate to a large degree and contain a lot of the individual tabber's own spin on the song. Not to mention that for the most part guitar tablature is not readily accessible from retailers. This is what I think anyway. Online tab sites are just not nearly as threatening to the music industry as the RIAA would have you believe. What do you think about this issue? Here's a good article which discusses this issue: http://www.theregister.co.uk/2006/08/29/guitar_sites_under_fire/
No, they would have been shut down because distributing copyrighted guitar tabs (and derivative works thereof) is illegal. You can distribute all the guitar tabs that you want to, so long as you own the copyright to them.