We're all tired of spam, you can be sure of that. It's good that Blizzard understands that the frustration of getting flooded by such inane ads or the like. The World of Warcraft's anti-spamming tool has been updated to the cover easy reporting when in groups as well.

The update was reported over the World of Warcraft Forums by Eyonix on the US side and Ommra on the EU forums. Generally, the announcements included instructions on how to use the said feature:

The new spam-reporting feature has been updated so that you can now report members inside your group or raid. This will allow players who are invited to groups created for purposes of spam to report the abuse appropriately.

To report this type of spam, simply right-click on the player's name in the chat interface, and choosing the "Report Spam" option. Once you have selected this option, a dialogue box will open to confirm that you wish to report the target player, and your report will be sent once you confirm your choice.

Please make sure you're only using this reporting feature for spam. All other forms of abuse should be reported appropriately, by petitioning a Game Master.