Is it worth the trouble?

I've realized talking to fellow students and occasionally postdocs that I frequently have to explain the same few topics over and over. Since I have my own personal notes on these things, I might as well write them up for people to read, since then I can just point people towards the notes. And if I'm going through the trouble of writing things up, maybe I should post them on an indexed, google-searchable blog? Why not? Maybe I will.