I've got one and many want one, but why do I have one? The primary reason is because I type around 100 words per minute. This mastery of typing doesn't come without a few typos and mistakes. My spelling impediment also includes a very wide array of grammar idiosyncrasies. 
"It's been a problem since I first started typing fast. I miss a letter or sometimes type the letter before it's place. It's been a struggle and embarassment to my ego.", says myself. He also stated that he was working to remedy the problem, and that spellchecker should be added to his blog system.