True, the apostrophe is not used in posessive pronouns like his/hers, however it used for proper nouns, like "That is John's car." So it is confusing in that way.
However, the way I approach the its/it's confusion is to think of the other use for the apostrophe, i.e. in a contraction. The apostrophe is taking the place of one or more letters. So, if you mean to say "it is", then you replace it with the contraction "it's" (in the same way that you replace "cannot" with "can't".)
Slashdot Mirror
IMAP Behavior Chart from gmail help:
https://mail.google.com/support/bin/answer.py?answer=77657
... a simulated Heartbreak Hill?
True, the apostrophe is not used in posessive pronouns like his/hers, however it used for proper nouns, like "That is John's car." So it is confusing in that way.
However, the way I approach the its/it's confusion is to think of the other use for the apostrophe, i.e. in a contraction. The apostrophe is taking the place of one or more letters. So, if you mean to say "it is", then you replace it with the contraction "it's" (in the same way that you replace "cannot" with "can't".)