Throw that money in the air: MongoDB (a.k.a. 10gen, which recently renamed itself after its core product) has just raised a $ 150 million round of funding from investors including EMC Corp., Salesforce, T. Rowe Price, Red Hat, Intel, NEA and Sequoia.

According to Bloomberg News’s sources, the company raised the money at a $ 1.2 billion valuation, which would make the startup the most valuable in New York.

Ask many of the folks walking around Midtown, though, and they won’t know what you’re talking about. That’s because MongoDB, founded by DoubleClick vets, makes enterprise software–specifically, a NoSQL database. Clients include Goldman Sachs and MetLife, but it’s mystifying to the average Joe.

Please remember, though, that it was enterprise software that turned Larry Ellison into an island-buying, catamaran-racing billionaire.

Bloomberg News says:

“We’re picking up an increasing share of the market and over time that could become a really significant share,” said [CEO Max] Schireson, who declined to discuss MongoDB’s valuation. “The volume and type of data and the consumer and developer expectations are so radically different than they were when the relational database was invented.”

Of course, even this valuation won’t be enough to get the startup the same amount of mainstream buzz as a consumer business. Unlike, say, Tumblr, it promises absolutely no pornography. But ask the gentlemen of Fab about how quickly adulation can go pear-shaped.

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