Leaving shouts on someone's profile

[Courageous Thunder Dash 7,825]

It would be really nice if everyone was able to leave shouts on someone profile. That way people's inboxes wouldn't be cluttered quickly with PMs (Even though you have the ability to delete personal messsages). I feel that this way, if you have something quick to say, it would always go through. 

[Princess Periwinkle 3,775]

That sounds a lot like a profile comment.