It doesn't seem like it has anything to do with server-side coding, so unless I'm incorrect, it's yet another entry into the likes of JSFiddle, CodePen, JSBin, CSSDeck, Dabblet, Tinkerbin, Liveweave, etc.
Codio is a complete, fully functional IDE, not a Codepen clone. We also have a lot of server side stuff coming out next week and server side support is an ongoing thing, as is offline editing, which will be coming out Q1 next year. We're still in Beta so we're listening hard!
