IDC, for the second year in a row, has named IBM the world wide leader in social software platforms based on market share. IBM was also the world wide leader in social software platforms in IDC's 2010 report.
The release of the report is very timely as the Enterprise 2.0 Boston Conference kicks off today. In this year's report, IDC looks at the social software market for the 2008-2010 period. In the report, you'll find revenue and market share for each of the vendors listed.
IDC reports that the worldwide revenue for social software platforms was more than $500 million in 2010. This represents an almost 32% growth from last year. IDC also mentions that they expect the market to grow to $2 billion worldwide by 2014.
It's also worth noting that Microsoft is not included in this year's list. Microsoft wasn't included in last year's list. This further validates that SharePoint is not an Enterprise 2.0 platform (unless of course you can find the budget to spend $6-$9 on services/customization for each $1 you spend on a SharePoint license).