So, to clarify:

The official policy has nothing to do with reverse DNS lookups of URLs.
AOL's policy prohibits linking of URLs using IP addresses.

The system they used to enforce the policy was/is quirky, as can bee seen here.

owner-nanog@merit.edu wrote on 10/02/2006 02:23:56 PM:

>
> On 10/2/06, Matt Baldwin <baldwinmathew@gmail.com> wrote:
> > > Yes, I'm noticing this too.  Very lame indeed.  Doing a quick Google
> > > on it in the Groups it seems that it was a feature that was enabled
> > > earlier this year.  My guess is they turned it off, then turned it
>
> Drew the attention of a friend at AOL to this and got a reply quoted
> below - this was apparently an issue at AOL's end. Thanks to AOL for
> quickly acting to fix this.
>
> I've been asked by my friend to post this below
>
> srs
>
> [quote]
>
> We found a problem with the way URL's were being identified and have
> undergone steps to correct it.  In the interim, the rule change has
> been backed out pending further testing.  Thanks to all on the list.
>
> [unquote]