Ten words you need to stop misspelling

There are a few words that are commonly misspelled or simply used incorrectly. I'm quickly becoming a fan The Oatmeal comics and today they've got a good list of ten commonly misspelled words, along with that special brand of Oatmeal drawing and comedy. The words they cover are:

Lose/Loose

Weird not Wierd

Their/They're/There

Your/You're

It's/Its

Definitely

Effect/Affect

Weather/Whether

A lot not alot*

Then/Than

Find the comic and explanations here.

* Also in this category there should be a discussion of ...