1. Email account activation. NONE
This is the most relaxed way to have a member enter the comunity. The new member joins the community by filling in the registration form and then he can start posting in just seconds. For many years in the "specialized" community people sustained this option: no emails with activation code, no head-aches for our new members.
The problem is that the Internet has changed a lot today. We don't deal only with legit members as we used to. The spammers and even spam bots are making the admins' lives harder. Even if this type of account activation (or lack of it in the end) would be good for the legit members, it also leads to many exploit possibilities from the bots and spammers. We advise against it now, even if 2-4 years ago we used this too.
2. User email account activation
One of the most used of the 3 types. Our members fill in the registration form and then they receive (usually instantly) an email with the activation code. The follow the link and then they are active members in the community.
The downside would be that the new member needs to log into the email account in order to validate the registration and many would consider this to be just too much for them. Still, on the other hand, people are getting used to this and they are already accustomed to this "register-validate game".
This way the admin ca controll the emails: there are some email services already known for the many spammers they host. By having this activation type enabled and banning some email accounts you'll be able to slow down the spam phenomenon in your community.
Some of the banning email settings we use:
*@*.ru (alll .ru emails)
*@cashette.com
*@gawab.com
TIP: Sometimes the activation email is sent into the bulk/spam folder of your new member. Make sure you write down in the registration page or the rules this situation. The email usually "leaves" in a second and they should get it instantly. Make sure you tell them to look into the bulk/spam folder too.
3. Admin email account activation
This is the activation type we use only when dealing with a persistent spammer or a banned member who just won't leave us alone. If you banned someone, there are chances that the person banned would try to enter the forums again. When dealing with this, try to set the account registration to admin activation for few days to be able to controll the situation better. This way you can disable access in the forums to the member giving you a hard time.
I hope this article helped you understand these permissions better.

