Why would you think the creation of this site might suggest that Microsoft is selling off its IP in relation to OpenType to Monotype? If Motorola created a site www.pentium4.org, would you jump to the conclusion that they were selling off that IP?
What alarmed me is that this domain was previously referencing Microsoft's documentation.
Also the fact that MonoType was sold by Agfa, with his name changed.
Also the fact that Microsoft's presentation of OpenType (previously TrueType Open, previously TrueType) has removed the reference to Apple's contributions in TrueType, leaving only Microsoft as the owner of the trademark and technology, also partly attributed to Adobe).
With Apple now supporting other layout tables, that are not referenced in the Microsoft documentations for OpenType, this really suggested me a branch split after disagreement (also increased by the new status of Monotype).
What is strange also is that the www.opentype.org web site is a page whose title refers to "Arial Unicode MS". Isn't it a Microsoft font? These things all combined are very intrigating.
Is there a way outside OpenType for other system vendors than Microsoft and Apple? This standard loks more and more proprietary...