- It lets my articles be re-used/re-posted in far more places I do want it to be used (Wikipedia, other places using the CC-BY-SA, etc...)
- I don't think anyone's going to plagiarize my work anytime soon - besides, at the very least, they have to give me credit (the BY clause).
Besides, I think the more liberal licensing terms make the blog more attractive to FOSS enthusiasts, which is a big plus for me since I need all the publicity I can get. Hopefully I'll see the rewards of switching to the CC-BY-SA license in a year or so. :)