I'm surprised they didn't call it Microsoft+. Wow, just when you thought Microsoft were heading in the right direction and climbing back to the top of the ladder, they go and build a social network nobody will use.
I thought the same until I saw that it was a research product/experiment. I think that makes it interesting and harmless rather than sad and misguided.
All Google products are released as experiments as well. It's just another buzzword oriented way of launching products and invalidating any negative or positive criticism of said product. Experiment = Beta.