Is internet activism actually worth anything?

[Brave Duck]

I've seen a lot of "activists" on social media websites who all seem to have a lot to say, but not really anything valid or overly useful, and I feel they mostly just state the obvious and re-hash the same tired points. So I inquire; is activism actually worth anything, or is it merely a self-esteem boost to the ethically insecure to project their emotions with?

I am talking about most internet activism in general, but in-particularly referring to things like Tumblr's social justice blogs.

Any answers on this, good or bad would be vastly appreciated.