CrowdGather Inc., an operator of online forums, announced on Monday that it has acquired a social-gaming company for $5 million. The Woodland Hills company merged with Plaor Acquisition Corp. and Plaor, a Boston startup run by former Microsoft, Disney and Sony employees that develops mobile and social-media games. The merger is expected to close before May 15. CrowdGather also said it would sell off some of its forum sites for about $1.9 million for working capital to promote Plaor game titles among CrowdGather users as it transitions to more of a social-gaming company. After the sale of the sites, it still expects to maintain about 80 percent of its users. “We believe that access to our user base is potentially a tremendous competitive advantage for Plaor’s titles and will improve the forum experience for our users where they will be able to play Plaor’s games against the forum community,” said Chief Executive Sanjay Sabnani, in a prepared statement. Shares fell 2 cents, or nearly 20 percent, to 8 cents in over-the-counter trading.