This one won’t be so easy, I suppose:
What is the WTF on this page?
PS. Bonus points for two WTFs detected!
Answer: As World_in_wireframe observed, the purpose of a captcha is to make it harder for automated scripts to submit forms. Having it in plain text and thus copiable defeats its purpose completely. WTF :)
The other WTF I thought about was the fact that it doesn’t seem to be required to enter the digits at all (doesn’t have the compulsory asterisk.) The grammar issues are candidates as well, although I didn’t notice them at first (shame on me!)