Well as the february 2002 anti-war protests against the iraq war showed, protests don't accomplish much. Especially, since the media always tends to marginalize protesters and their view points (I'm thinking of the WTO protests/anarchists / agent provocateurs). The Tea Party was different in that it got a lot of support from Fox News. Which larger protests (i.e. the iraq war one) have been dismissed.
I think the most ironic thing though, was the purchasing of one million tea bags (I believe they purchased them) and complaining about wasteful spending. Not to mention the elaborate costumes that apparently some people must have had laying around.
Overall though, I like protests and support them. I think many people had valid points, although most seem to be simply saying Democrats =evil. Nonetheless, I don't think it will have much effect - mainly because of the cheerleading that makes it seem disingenous in the eyes of those more to center or left.