MS Office 2007 will have native support for ODF, meaning much more and beyond the import and export facilities. Microsoft’s OOXML has been already accepted has a standard, so this announcement seemed a little out of place, especially because ODF and PDF get support from Office before OOXML does.
It is definitely good from an interoperability perspective, and it is commendable that Microsoft has started to think of path towards its interoperability promise.
This will make the ODF format accessible to big number of MS Office users. However, this also means that once they start using ODF, they can migrate to other office suites which support it. Especially so because the costs involved might vary a lot, and projects like OpenOffice, KOffice and AbiWord are open source projects. Worst, this might also lead those, who use Windows only for MS Office, to their migration to other operating systems.
I am sure Microsoft has thought about all this much before I have. In fact, I see this as one of the core reasons for the whole saga of creating another standard. So, although I appreciate the announcement and the intentions, I doubt that more information and reasons are on their way.
The ODF enthusiasts can take advantage of this, and create an awareness campaign for the laymen. The fact that ODF is accessible across various office suites on various platforms can motivate them to adopt it. I think this announcement can be used positively to spread ODF goodness to MS Office users.