Ok... I'll weigh in my 40 cents.
The site was totally free for about 5 years. For instance, we'd publish the entire songs or tabs along with MP3 files.
Over the years, we've made it a point to hire the absolute best guitar players on the web to post lessons here.

Unfortunately, due to recent legislation, a whole bunch of Tab sites have been legally shut down for publishing copyrighted tabs.

We don't want to take the chance that our site gets shut down, so we did a major overhall of every trick on the site (not an easy task since there's over 3000 over them).
We've tried our best to weed out any copyrighted material. In the meantime, just incase if legal problems, we've had to hide the member lessons just in case of copyright infringment.
There's a whole legal page listed here that goes over the legalities of this

http://www.guitartricks.com/updates.php

http://www.guitartricks.com/legal.php

Basically, to boil it down... we're allowed to print small excerpts of copyright files as long as they are being used as exercises and part of a lesson.
Anything more, and we may end up in trouble.

So the short answer is, unfortunately we have to post just small portions of copyright text...
The advantage, is that the other tabs may be abailalbe