Restaurant City will be taken offline from both Facebook and the App Store on June 29, according to a Wall Photo added to the game’s album today. Players are being encouraged to move to The Sims Social both with a virtual currency bonus and the ability to convert existing Restaurant City premium currency to Sims Social premium currency.

Playfish’s Restaurant City was one of the top restaurant simulation games on Facebook in 2009; it maintained that momentum through 2010 after EA acquired the developer. The game recently marked its third birthday on Facebook in April — having shrunk by more than 90% in size from its peak numbers of 5.2 million daily active users and 18 million monthly active users to today’s 310,000 DAU and 1.8 million MAU, according to our AppData traffic tracking service. The real problem seemed to come for the game around September 2011 when retention (which we can measure by taking DAU as a percentage of MAU) dropped below 20 percent. Restaurant City rallied in October around the time its iOS version, Restaurant City: Gourmet Edition, received a major update — but retention dropped again in early 2012 and Gourmet Edition fell off the top apps lists.

As a genre, restaurant sims still show some growth on Facebook and mobile when they first launch. The games lack staying power, however — we still see Restaurant City as the second-largest game in the category on Facebook after Zynga’s Café World, which is also in decline.

As a company, EA is apparently struggling to maintain its position as a top developer in social and mobile. It’s slipped to the No. 4 position of top developers on Facebook by DAU and wooga is about to overtake it for the No. 2 position on MAU. On mobile, the developer pulled two titles from the App Store for poor performance in as many months this year. EA has also lost a lot of its staff to Zynga in the last 12 months and is now rumored to be facing layoffs, though the company has denied it. EA reports its Q1 2012 results next week.