So what has motivated Sony to jump in and help Olympus?
I recently have been dabbling pretty extensively in the Olympus MFT gear with my E-PL3 and now an OM-D. I like the gear and the quality is high(with the OM-D). It generally matches APS-C DSLRs which is what I was using before.
I have been reluctant to drop my big-boy camera gear (canon) and go whole hog into MFT because I have less confidence in the solvency of Olympus and of MFT in general...particularly when you consider that the only two members of the MFT consortium are Panasonic and Olympus and they are both marginal players in high-end--or more accurately--mid-end camera gear.
So, the Sony investment is a curious one for me. They undoubtedly have a winner in their NEX range of cameras, but the general criticism of them has been that their lenses are large and slow. Having handled them, I don't really care for the feel. On the other hand, Sony clearly is making some of the highest quality sensors in the digital camera marketplace. I think I recall that the famous D800 sensor is sourced by Sony.
So it would seem that the strengths and weaknesses of Olympus's MFT alongside those of NEX make for a congruent match, but one company would hypothetically have to give-in and take the format of the other. Doing so for Olympus nullifies the MFT lens investment. Doing so for Sony nullifies a pretty great entry into the mirrorless segment with the NEX cameras.
Does Sony go MFT along with Panasonic and Olympus? Is APS-C truly dead, and is the sweet spot for reduced-sensor-size high-quality photography really lay at the MFT size?