Online games
"Online gaming is a technology rather than a genre; a mechanism for  connecting players together rather than a particular pattern of  gameplay." Online games are played over some form of computer network, now typically on the Internet. One advantage of online games is the ability to connect to multiplayer games, although single-player online games are quite common as well.
An online game is a game played over some form of computer network. This almost always means the Internet or equivalent technology, but games have always used whatever technology was current: modemsterminals  before modems. The expansion of online gaming has reflected the overall  expansion of computer networks from small local networks to the  Internet and the growth of Internet access itself. Online games can  range from simple text based games to games incorporating complex  graphics and virtual worlds populated by many players simultaneously.  Many online games have associated online communities, making online games a form of social activity beyond single player games. before the Internet, and hard wired 
The rising popularity of Flash and Java  led to an Internet revolution where websites could utilize streaming  video, audio, and a whole new set of user interactivity. When Microsoft  began packaging Flash as a pre-installed component of IE,  the Internet began to shift from a data/information spectrum to also  offer on-demand entertainment. This revolution paved the way for sites  to offer games to web surfers. Some online multiplayer games like World of Warcraft, Final Fantasy XI and Lineage II charge a monthly fee to subscribe to their services, while games such as Guild Wars  offer an alternative no monthly fee scheme. Many other sites relied on  advertising revenues from on-site sponsors, while others, like RuneScape, or Tibia let people play for free while leaving the players the option of paying, unlocking new content for the members.
After the dot-com bubble  burst in 2001, many sites solely relying on advertising revenue dollars  faced extreme adversity. Despite the decreasing profitability of online  gaming websites, some sites have survived the fluctuating ad market by  offsetting the advertising revenue loss by using the content as a cross-promotion tool for driving web visitors to other websites that the company owns.
Browser games
As the World Wide Web developed and browsers became more sophisticated, people started creating browser games that used a web browser as a client. Simple single player games were made that could be played using a web browser via HTML and HTML scripting technologies (most commonly JavaScript, ASP, PHP and MySQL). More complicated games such as Legend of Empires or AQ worlds would contact a web server to allow a multiplayer gaming environment.
The development of web-based graphics technologies such as Flash and Java allowed browser games to become more complex. These games, also known by their related technology as "Flash games" or "Java games", became increasingly popular. Many games originally released in the 1980s, such as Pac-Man and Frogger,  were recreated as games played using the Flash plugin on a webpage.  Most browser games have limited multiplayer play, often being single  player games with a high score list shared amongst all players.
Browser-based pet games are also very popular amongst the younger  generation of online gamers. These games range from gigantic games with  millions of users, such as Neopets, to smaller and more community-based pet games.
More recent browser-based games use web technologies like Ajax to make more complicated multiplayer interactions possible.


