In-browser emulation. http://www.bit-tech.net/news/gaming/2014/11/03/internet-archive-unleashes-900-arcade-class/1
Should keep all those old games alive as long as they are supported in future browsers, I recently discovered the Mega EverDrive - SD Card Flash Cartridge for the Sega Genesis which enables you to play 100's of ROMS on the console, it really makes me want to dig out the Mega drive This vid is quite old but the Everdrive is still available.
What do you mean? This hasn't just gone live today - I've been getting my River Raid fix from there for months. As far as I'm aware, the site has been up for years.
Mentioned on a prominent IT/Gaming site and shortly afterward is down for maintenance? I'm just guessing but probably had a large influx of people looking at the site who don't normally.
I'm thinking The Internet Archive could handle a little Slashdotting. They've got more bandwidth than God: they typically have more than three million unique IPs visiting each and every day and average around 30Gb/s of sustained bandwidth from three data centres in the US. Far more likely the software broke than a story on a gaming site brought them to their knees!