How does It work- Spammers/Bots

[Azbubu]

So they create myBB accounts, using randomly generated usernames? Then log into a randomly generated email account they provided to activate their myBB accounts? All without human assistance?

 

[koeksGHT]

Easy enough.. without a good captcha system

 

[Messugga]

Sometimes with minimal human interaction, such as to complete the captcha forms. It's not too crazy to write a python script to handle registration and whatnot for you.