Valve sneaks in-game ads into DOTA2

A post on the DOTA2 subreddit has shown the world that Valve has just sneaked in some form of in-game ad for DOTA2, which popped up onto a Redditor's game asking them if they'd like to buy a Charm of the Defender's Vision.

You can click 'No Thanks!' but this still doesn't take away from the fact that Valve just slipped in-game ads into their games. The title of the post in the DOTA2 subreddit is pretty harsh, and rightly so: "Valve has now introduced IN-GAME ADS, I hope nobody is ok with this."

What do you think about Valve introducing in-game ads to DOTA2?