YouTube says it will redirect people searching for "violent extremist propaganda" and offer them videos that denounce terrorism.
People searching for certain terms relating to the so-called Islamic State group will be offered playlists of videos "debunking its mythology".
YouTube said it wanted to help prevent people being radicalised.
The company told the BBC that uploading IS propaganda was already against its terms and conditions.
So YouTube are joining the fight against terrorism by attempting to stop people watching propaganda videos. I have no doubt they can do what they say they are going to to a certain degree, but - as with all things in the world of technology - I have some doubt that it will be successful.
Firstly, while it is the biggest and most popular, YouTube is not the only video sharing site out there, and if ISIS (and whatever ISIS morphs into after it is defeated) want to share their videos, they will find other sites to share them on.
Secondly, if YouTube stop searches for specific terms and redirect those searches, what is to stop ISIS planting videos under terms such as "cute kittens" or "dancing elephants"? In the same way that the arms race between those who produce computer viruses and those who stop computer viruses is literally just that - an arms race - the battle between the tech girls and guys at YouTube and the tech guys at ISIS is just going to be a battle. You stick your finger in one hole in one dyke, and the next hole pops open.
I am not advocating for keeping propaganda videos on YouTube, or for YouTube just giving up, but I am not convinced it will solve the problem. I think it will just shove it on to someone else - Facebook, MySpace (does MySpace still exist?) or wherever. Somewhere that might not be so civic minded. And since it isn't clear if YouTube is doing this out of the goodness of its heart, or because the FCC (or whoever regulates the Internet in America) has a gun pointed at its head, it might lead to other sites being shut down because they can't meet the requirements to do it.
So will it work? Will YouTube defeat ISIS on the propaganda front? Or will is this simply going to drive ISIS further into the dark corners of the web and make them much harder to find?
What will this lead to?