Alright, this might be a little hard but I dunno, I'll just request it as I quite need it. What I want is, that if a new user signs up and posts at my board, I (admin) has to approve the first post they make before they can post anymore. That is a great way to determin if a user is going to be a spammer or not. I'd also like an option that makes an admin able to choose how many posts of a new user would need approval. Thanks in advance!

Would it be okay if, instead of that ^, have a specific usergroup, in which all posts are moderated, then you can manually move them out of the usergroup if they seem okay?

That is okay too. As long as they stay in that usergroup when they register first.

you can define the usergroup that new users will be added after registration, that usergroup will be moderated. when you think a user is ok you promote the user to the normal group.
but I don't sure if there is a way to promote the user directly from the thread page, there is?

Well, here's a plugin which should do the trick.  Just adds a setting under Board Settings -> Posting where you can specify the usergroups you want moderated.

Thank you, it's great so far. However, it's not very optimal yet because of the following reasons and I'd like a little extra plugin for that so it works perfectly.

This is the problem.

If new users join and active their account through email, they get in the Registered usergroup. Now I don't want to have to approve all posts of that group as I already have hundreds of active members in that group. So one solution is a plugin where you can create a new usergroup where people who activate their account go in first. Then when they post I have to approve posts from THAT group and I can move them to the Registered usergroup myself if they're good.

OR, what also could be a solution is that you ONLY have to approve posts from Registered members that are new, that have 0 posts except for that 1st post that has to be approved.

Thanks in advance, I really appreciate it.

Just make a separate group, and call it "Registered".  Rename your current group to something like "Moderated".

Then, to move all your users in the Moderated group to Registered, run a query like:

(obviously, replace New Group ID etc with the appropriate values )

Aww crap I don't have access to my forum's database. =/ Well I guess I can do it 1 by 1. Thanks

How can you have a board set up without access to the DB???

If your host doesn't provide you with some front-end, you can always set up phpMyAdmin on your server, or use a MySQL client to access it (if the host allows it).

No, it's because I'm not the main head admin of the forum and because I get hosted on a server by a friend of mine, I don't get access to it because he hosts multiple sites on one server and he doesn't want clients to get access to everything. But I can inform him and let him do this with no problem, so there's nothing to worry about.