Microsoft Corp., looking to sell more of its software online, released Web-based versions of its Exchange and SharePoint programs for helping workers at smaller companies to collaborate.

The company also said it has won more than 500,000 users at customers such as Pitney Bowes Inc. for a version aimed at larger businesses, introduced last year. Two-thirds of those switched from rivals, mainly International Business Machines Corp.’s Lotus program, Microsoft senior vice president Chris Capossela said.