Facebook may be the world’s dominant social network, but a number of high-profile investors are betting that there’s room for platform players in the space.

Backplane describes itself as a “start-up uniting people around interests, affinities and movements”, but it’s best-known for running Lady Gaga’s LittleMonsters.com, which is in private beta.

Sequoia Capital, Greylock Discovery Fund, Battery Ventures, Formation 8, Advance/Newhouse Investment Partnership, Google Ventures, Founders Fund Angel, Menlo Ventures, SV Angel, i/o Ventures and a number of high-profile individuals participated in the company’s Series A round, which the Wall Street Journal pegs at $4.5m. That’s on top of the $1-1.5m it had previously raised from investors who reportedly included Lady Gaga herself.

Interestingly, according to The Wall Street Journal’s Lizette Chapman, the Series A investment was structured as a convertible note “to create more flexibility when The Backplane raises a Series B round–an event [that] could occur ‘rather quickly.'”

And it’s not difficult to see why: Backplane is on a shopping spree. Its first purchase: Cortex, a “web-based sharing platform” founded by one of Backplane’s co-founders. Next up: lots of engineers and senior executives.

Backplane CEO Matthew Michelsen explained, “We’re looking to hire some very senior people right now. If we wanted to recruit the head of YouTube, for example we couldn’t go to them and say, ‘We’ve got nine months of capital in the bank.’ They wouldn’t leave their job and join us for that.”

Currently, the company employs 15 people and has two offices, one in Palo Alto and one in Los Angeles. According to Michelsen, his company is generating revenue and has spent “less than $1 million so far to develop the community platform that will ultimately combine calendar, email and social networking functions, including Facebook and Twitter, along with photo sharing and multilingual chat functions.”

So is Backplane destined for success?

That’s questionable. Lady Gaga’s involvement with Backplane masks the fact that much of what the company is doing isn’t new. CEO Michelsen previously described his company’s goal:

The goal is for everyone to start their own interactive community. If you’re a Girl Scout mom, you could have your own Backplane with 12 other moms.”

Notwithstanding that for many, Facebook is that “interactive community”, Backplane’s challenge is that plenty of platforms already exist for those looking to build communities outside of Facebook. From Jive and Ning to BuddyPress and vBulletin, Backplane will have to hope that the millions of dollars it’s spending buying technology and hiring engineers will produce more than functionality that is largely commoditized.

If it doesn’t do something incredibly unique and innovative, it may prove to be this bubble’s poster child for celebrity-backed excess.