Gina Bianchini's abrupt March departure from Ning was a surprise; in two years she'd taken the social networking company to an "eye-popping" $750 million valuation from just $170 million. Did she do it honestly?

Or did Bianchini put one over on Silicon Valley venture capitalists and one of their golden boys, Marc Andreessen?

We hear Bianchini fiddled with Ning's financial and traffic numbers in selling the company to its last round of investors. And not just the forecasts, which are routinely pumped up by Silicon Valley entrepreneurs to wishful-thinking venture capitalists, but actuals. It was the discovery this fakery that purportedly led to her March ouster. (If you've got other details, fill us in.)

Andreessen, Bianchini's ex-boyfriend and fellow Ning co-founder, is said to have been too close to Bianchini to spot the deception. He certainly arranged for a soft landing, naming Bianchini an "executive in residence" at his venture capital firm Andreessen Horowitz.

Hiring such an advisor hire must have been painful for Andreessen: As the co-founder of Netscape Communications, whose initial public offering launched the first dot-com boom, he earned himself the role of Valley Svengali, whispering in ears at companies like Facebook and eBay, where he sits on the boards, and at Skype, where he holds a significant stake. But when it came to the dark art of founder-investor relations, Bianchini still had plenty to teach him, apparently.

The chatter about Bianchini could well be overheated, of course; dodgy counting is starting to look like a third rail in the Valley. Gossip about Bianchini's departure resembles, for instance, similar speculation about Jay Adelson's departure from social news site Digg, centering on whether co-founder Kevin Rose pushed Adelson aside over concerns about the traffic-stat-juicing effects of the DiggBar redirection service.

It's a positive development that more Valley investors are turning over rocks and looking for signs of fraud. In the first dot-com boom, the one Andreessen rode to microfame and fortune, the inherent shadiness of all numbers was taken for granted. These days, VCs have apparently raised their expectations. And in this brave new world where investors are supposed to keep a closer eye on their founders, it was probably wise of Andreessen to keep Bianchini nearby. He's still got some remarkably slick entrepreneurs to keep an eye on, after all.

UPDATE: Andreesen called the Bianchini rumors — and our post — "completely fabricated slander" on a the locked-down social network Quora: