diner dashBig Fish Games has launched a multi-year strategic alliance with casual game developer and publisher PlayFirst. It’s a sign that, even on the web, distribution still matters.

Under the deal, Big Fish Games, which has more than 2,5oo games, will take over the PlayFirst web site, putting both Big Fish and PlayFirst games on it. PlayFirst, meanwhile, will concentrate on making its own games and will give Big Fish a 30-day exclusive on them.

Mari Baker, chief executive of PlayFirst in San Francisco, explained it this way: In the past, PlayFirst focused on developing, publishing and distributing its own games. The latter part it handled by publishing the games on its own web site as well as on other casual game sites. Now it will stop focusing on distribution, which Baker said is something that Big Fish does well. Big Fish can handle infrastructure tasks such as payment system, electronic commerce, and customer support.

This will allow PlayFirst to redirect resources to higher priorities, such as making games for platforms like the iPhone,  Facebook and Xbox Live. PlayFirst has had a lot of hits related to its Diner Dash game, where Flo the waitress has to juggle plates and customers to keep everybody happy in a busy diner. Many of PlayFirst’s games focus on female gamers.

Jeremy Lewis, chief executive of Seattle-based Big Fish, said that his company has had a long and profitable partnership with PlayFirst. This move will help serve Big Fish’s goal of getting more premium content for its own site and for its distribution business. Big Fish has 400 employees and is now expanding to an office in Cork, Ireland, as part of a move to grow its business worldwide. The company doesn’t release financial results, but Lewis described 2009 growth as “extremely robust.” The company is profitable.

During the recession, casual game companies such as Big Fish have taken a hit, partly because downloadable web games that once generated $20 now generate only $7. To try to set itself apart, Big Fish has relied on high-quality, unique games such as its recent Harlequin romance game. PlayFirst fits with that approach. Big Fish, founded in 2002, raised more than $83 million in funding in 2008.