There's been a lot of fuss about this horrible word verification thing that crops up on people's blogs. Blogger makes it happen automatically and a lot of people don't like it but don't know how to change it. I hope this helps. Please note that I'm still on the old interface. If you've updated I don't know if this will work.
Go into your dashboard and choose the settings tab, then comments. Like this:
Then scroll down to this bit:
Take off comment moderation and choose 'no' for word verification.
Don't forget to hit the Save Settings button at the bottom.