I'm not sure how well received it would be, but sometimes people include the link to the post where they expressed their disdain for a certain behavior. If you feel it is important, you can include a link and then ask about the incongruence.
I wasn't thinking of the forum in general. I was just using it as an example as I don't have any specific examples.
As far as the forum goes, if I see an inconsistancy in a poster, I will just generally ignore them and thier "advice". I know in principal that should work IRL, but, I didn't know if there was a way to say anything and still be polite.
GLaDOS: You have a point.
I know there are people that are hypocrites without even realizing it, whether it be because they are just dense or don't see themselves in the same way they see others. There are others that just don't care. They do what they want, offer opinions based on their life philosophy regardless of whether they would do the same.
IF the person was the former, I think bringing it up to drop it, lets them know that they did *badthing*. If it's the latter, it most likely will do nothing but make a person defensive and the conversation will not be productive.