Yes, Online gaming has become really popular these days . Big companies are investing huge money in online Games and apps. Try Prince of persia (flash game version, Mochi media game ) , here :- http://onlineaddictivegames.com/poptfs-core-game/
I'm currently playing League of Legends, Dota 2, any Steam game on sale (Steam is taking all my moneh!), and any available free game on Kongregate.
Hex Empire is by far one of the best free strategy games I've seen. Each level is like a puzzle and it can be really challenging.
recently i play this online game, its addictive. based on zombies. you guys must check this http://onlineaddictivegames.com/zombie-cant-jump/
Many people are playing on-line games this days, but I believe - if you play for sometime just for fun or timepss, it is OK - otherwise its an addiction and waste of time.