There are good arguments on both sides of the fence on this one. The traditional side thinks that releasing a beta product tarnishes your image by having users use an unfinished product.
The new tech side of the story is that it makes for a better product if users help shape and test it, and that there isn’t a great way to test these applications without just opening them up to a large user base.
I can see both sides of it. It really doesn’t bother me much, although I think it’s become a cliche’ at this point as a Web 2.0 application to be in beta.
The bottom line to me is that it’s meaningless. Most web sites and web products these days are constantly evolving and improving, so isn’t saying it’s in “beta” just an excuse for it to not work correctly? If a customer complains, you can just say it’s in beta right? Weak.