[MightyMidget]

So how does it work?

Basically you create a string for each category/ID, the most basic form for e.g. ID "Anal" would be:
"ANAL: Anchor text1 | Anchor text2 | Anchor text3"
Here | is the separator and there are three possible outcomes (each with a 1/3 chance of being shown).

You also have the {} which is an "inline" version of |
E.g.
"ANAL: {Hot,Lewd,Dirty,Sexy} {anal porn,buttfucking,ass stuffing} | Up the {ass,butt,asshole}"
The first part(Hot,Lewd,Dirty,Sexy} {anal porn,buttfucking,ass stuffing) has 4*3=12 possible outcomes, for example "Hot anal porn" or "Lewd buttfucking".
The second part (Up the {ass,butt,asshole}) has 1*3 possible outcomes, for example "Up the ass" or "Up the butt".
So all in all you have 12+3=15 possible outcomes for this string!

If this seems confusing to you, it really is quite simple! Just look at the test page I linked to above, do a few refreshes, and you will see the output of different strings.

As far as using the script on your site, it's as simple as replacing the text of each recip's anchor to this: <? RT("NAMEOFID") ?>
And that's it, you have dynamic anchor texts!