I don't know why it bugs me so much, but why do so many people misspell "definitely"? (Or "definite", etc.?) Maybe it's because they mispronounce it, too, because they have lazy American speech patterns, like "nukular". Pronounce it "deaf in it lee".
At any rate, the word is definately not spelled "definately". It is definitely "definitely". This is one of those errors that, when you fix it, results in your readers' opinion of your IQ rise about 15 points.
Other than that, today's not been bad so far.
Update: Jamie Spencer, publisher of the fine Austin Criminal Defense Lawyer blog, has politely pointed out that one of my sentences above (now italicized) could be, um, improved. I would have been a lot less polite. I'm too proud to try scanning it and counting the errors; you may amuse yourself with that task if you like. Here's my stab at an edit, though.
This is an error that, when fixed, will result in your readers' estimates of your IQ rising about 15 points.
That's still awkward, but it keeps the meaning of the original sentence. Definately better.