Google Plus, the ambitious company-wide social network launched late last month, was reportedly built in secret over an extended period of time by scores of engineers and social software designers brought into the company through a campaign of heavy hiring.

The scope of Plus's ambition is far from fully realized, though, and apparently the expansion of the team isn't complete yet either. This morning a well-backed little startup called The Fridge announced that it has been acquired by Google and will close its group sharing app up to work on something similar at Plus. It was the second little startup like it to be acquired by Google in the last two days: yesterday YCombinator alum Scoopler/Just Spotted announced the same thing.

Did these little startups show promise and get multi-million dollar signing bonuses, effectively, as acquisition/hires? Or did they see the successful launch of Google Plus as writing on the wall: that the real time and group sharing market has now matured enough that it's time for anyone small to team up with a giant if they are going to survive? Maybe they began building a year ago with insiders' knowledge that flipping to Google would become an increasingly viable strategy.

Liz Gannes at AllThingsD reports that Fridge focused on collaboratively edited groups, a feature which, by all indications, is coming to Google Plus soon. Internally, she says, Google employees refer to the feature as "shared circles." Those are going to be a whole lot of fun to build and share. Hopefully they won't have limits like Twitter's limits to 20 Lists per account and 500 members per List.

"Right now, Google Plus is asymmetric," Fridge founder Austin Chang told Business Insider. "We're going to help them create shared spaces." Business Insider's Alyson Shontell points out that none of this is entirely new, either. "This isn't Chang's first exit. In 2005 he sold a social game, Popularity High, to MTV/Viacom for an undisclosed amount." Apparently Chang is unusually in touch with what it's like to think like a teenager, in a popularity/MTV/friend freshness kind of way.

Perhaps purely neither build nor buy, Google's strategy could be called "buy, eat, build upon."
Whatever the magic is, glamorous investors bit, that's for sure. Liz Gannes says The Fridge had raised $800,000 from investors, including Mitch Kapor (creator of Lotus 1-2-3), Naval Ravikant (Venturehacks and Angel List), Keith Rabois (PayPal, now Square), Jim Young (co-founded HotOrNot), Jeremy Stoppelman (Yelp co-founder), Jameson Hsu (Mochi Media advertising), Geoff Ralston (built Yahoo Mail, sold Lala to Apple), Jason Sander and Joshua Schachter (founder of Delicious).

With backers like that, the four person Fridge team may have been invited to the Google Plus Christmas Party whether they had been acquired or not. Yesterday's acquisition/hire, Scoopler, was backed by Silicon Valley investment leader Ron Conway, among others.

It's hard to imagine such well-backed startups, with silly names like The Fridge: Keeping Your Friends Fresher, were ever intended to have any other fate. Maybe that's not fair, maybe there was a time a year ago when Valley insiders thought a new social network like The Fridge could become the Yelp of the future. It seems just as likely, though, that these insiders knew Google was preparing for a major push in social software (it had to, lest Facebook eat its lunch) and thought that an outsider's best strategy was to build to flip. I don't know.

Features

What's more interesting, perhaps, is where this points to for future features of Google Plus. It's also very interesting that these startups are being acquired now, weeks after Plus's launch, instead of before the launch.

One startup that did get acquired to work on social at Google almost a year ago was Angstro, an experimental social-graph and news-crunching startup lead by technical heavyweight Dr. Rohit Khare. As we wrote at the time of that deal:

"What does it mean to see someone like Khare join people like Joseph Smarr, Bradley Horowitz, Chris Messina, Brad Fitzpatrick and most recently Slide's Max Levchin? It means that Google's entry into social networking is going to be big, ambitious and probably engage heavily with the data-portability paradigm that has positioned itself as the strategic antithesis of Facebook."

We haven't seen a lot of that data portability stuff yet, but it's still a safe bet that it's coming, and leading with User Experience is a wise move. This week's two newest acquisitions appear consistent with that strategy.

If you were my Plusbuddy, we would have already been discussing this article before it was posted here.