If you've ever received spam in the form of an iMessage, it's a good idea to report it as junk to Apple.
While you've always been able to report iMessages as spam, you can now do it in a lot fewer steps if you're running iOS 8.3 or above. Reporting junk iMessages will help Apple to remove spammer accounts from their servers, making iMessage a much happier place for everyone. In order to report an iMessage as junk, just follow these steps:
Full story from the iMore Blog...