as far as anonymity goes.  

You are right about IP addresses, but tracking that is so rare for LE.. I haven't seen it happen as far as this line of business goes...but LE HAS looked up clients name and address from AOL POSTERS.  Don't use aol for posting.  Just don't.  
Today, I don't think you need to worry about IP tracing, but you do need to ditch the AOL account.  AOL can and does give up your name and address to any law enforcement body that asks, and there does NOT need to be a court order.  AOL is like DISNEYLAND when it comes to your privacy, they err on the side of being PC  politically correct...
use a big boy system, not AOL.  anytime you have to pay for and insert your real name, its ..DUH..not anonymous.
But I'm sure 'surelyyoujest' could give you guys even better recommendations for what service to use  My vote is just 'anything but aol'  but a techy person can give you even more advice