I literally never openlimp online. I play 6max NLHE.

I read this today at "http://forumserver.twoplustwo.com/showthreaded.php?Cat=0&Number=8009768&page=0&vc=1" :
If the players left to act all have miniscule PFRs, you can limp with extremely speculative hands and expect to see very cheap flops, giving you marvelous implied odds. Take advantage of it.
Isn't this bad advice? Also, by raising you increase your chances of having position postflop. If you limp you could get a few extra limpers behind you.

What are the fundamental reasons for raising preflop rather than openlimping?
To take control of the hand.
To use your position.
To build a pot.
To isolate players.
To play a flop with fewer opponents.
To steal the blinds. (almost forget this one!)
What else?

I also rarely limp when noone there have been no raises before me (ie only limpers). I will either raise or fold 95%+ of the time in this situation.

When there is a raise before me and I'm on the button with a hand I want to play I will often just call. This is very dependent on my table image though. If I don't have a loose image and I haven't been 3betting preflop a lot at the table, I will raise a wide range of hands that I want to play, like T9s.
Often I do have a loosish image and have been 3betting quite a bit, so I will call with a hand like T9s rather than raising it.
Is this OK?

Also, how should you play hands like AJ and AT pf? Is it better to 3bet AJo on BTN with a raise before by a standard player, or is it better to just call? or even fold? (I'm talking 6max btw).

A lot of different questions and ideas in this post, I would like to hear others thoughts on all parts of the post.