You are correct. It is why I chose to explain how I handle spamming in general, and then how it stops spam-bots from making posts (the last line of my first post). It also helps deter new members who join to just advertise from doing so as well.

Ah OK - missed that. :)

To stop bots (as opposed to humans or human-assisted bots) from registering, the vB3.6(.4) Image verification (CAPTCHA) has not been broken yet if set to use some more advanced features (random font etc...). No modification needed for that.

Nice list, but you also cut out ALL Russian addresses.
Even mail.ru and web.de are oubtfull. Those are versions of hotmail. Used by spammers a lot, but also by valid users from those countries.

Edit: I use agressive mail banning and then block words like "login" they often use at free mail servers. This banned spammers effective enough to keep web.de open for example.
Banning single msn.com addresses is not that usefull I think. Spammers used that address a couple of days and then move to a new one.

I noticed that often the same IP addresses are used, so I ban those IP-addresses. After I started doing that, the amount of spammers grew less soon.

True...but it is VERY difficult for people to verify the image. I have 20/20 vision, and I struggle with Image Verification(CAPTCHA) on vbulletin boards. The current Image Verification is so tuff, it drives members away.

SPAM BOTS do not think. They process data. The simple solution is to create a question and answer. Then you do not need Image Verification. Look at the amount of posts in this and .com's forums about spam. Obviously its a problem on a lot of vBulletin boards. Perhaps vBulletin should rethink about adding the NO SPAM mod to their software.

I was looking for a mod to prevent users from using links in the signature until they reach a certain number of posts...

its weird, i been running a forum for 2 years now and i have never seen anything like this!

You dont need a mod for this, but it is easier with a mod if you don't know how to create it.

Create a user group titled "Signature allowed."

I require 50 post before a signature is allowed.

I use a 3rd party registration system that has stopped 100% of all spam before it starts

It will be an ongoing fight.
For now this mod works, but when it is udes often enough, then spammers will produce something to crack it. And they will be able to, since the question has to be something everyone can answer.