Message awaiting moderator approval?

some friends recently came accross this on completly normal messages, and they seem to never be apporved, is this some sort of bug or something? is it a new feature?

 

My first few messages had that when I initially created my account but were approved on the same day. Some probation period for new accounts I guess

 

they probably temporarily enabled it due to a spambot attack yesterday.

 

thanks for the insight, i had never seen that so i assumed it was a bug since the messages took like a day to get approved