I really really get upset when people don't spell things right. And in the blog world, it may not be deemed important but it says to me that the author can't be bothered with details. So I wonder how can their grander vision be trusted?
This may sound picky, but I do think that if we can't be trusted with little things, we can't be trusted with bigger ones. Kind of sloppy. Language is important, it is our tool for communication and it needs to be used properly. Spell check is only a click away.