Re: IBM patents,
IBM has an interesting, and quite unique strategy regarding IP. About 20-25% of IBM patents are software patents, and IBM uses this patent portfolio to protect open source projects, especially Linux (http://www.linuxplanet.com/linuxplanet/opinions/7034/1). Also, IBM historically abandons a large portion of its issued patents (http://www.patentlyo.com/patent/2012/03/ibms-patent-abandonm...), and the abandoned patents become prior art, protecting everybody.