image via Bijan Sabet's Tumblr

Along with their announcement of a $85 million series E funding round earlier this week, Tumblr offered some statistics on their explosive growth. Most impressively, perhaps, was the fact that the site now does 12-13 BILLION page views per month, an astronomical increase over this time last year.

But these numbers are perhaps even more staggering: Tumblr has only around 13 million users and 30 million monthly unique visitors producing this massive pageview count. The people who spend time on Tumblr, it seems, are highly-engaged, and that's what convinced the venture capitalists from Greylock Partners, who led this round,  that real revenue and even profitability, is just around the corner. "They will succeed in working through that over the next months and years,” John Lilly, a partner at Greylock, told Reuters.

Bijan Sabet, of Spark Capital, one of the company's original investors who sits on Tumblr's board, said the rapid growth over the last year has given Tumblr the scale they need to monetize. "I think now the important role models are companies like Google and Facebook. Once you have a network at scale, you can begin to advertise in a way that doesn't feel invasive, that adds value instead."

Although Tumblr founder David Karp has said on several occasions that he doesn't want advertising thrown up on people's blogs, Mr. Sabet says that was natural at the time. "People need to remember that a year ago this company was tiny, around ten people who had raised ten million dollars. I don't think there is any shame in the fact that they choose to focus on users and product as opposed to generating revenue."

The critical question now is how to monetize a Tumblr pageview. As Mr. Sabet pointed out, the majority of these pageviews happen inside the Tumblr dashboard. So in many ways, users consume content here more like a stream of messages on Twitter than a traditional media property, where one page links to the next and users are driven from article to article.

Another issue with the dashboard is context. Google search is a powerful mechanism to pair against advertising because a search query offers a very specific context about what users are interested in. A typical Tumblr dashboard, by comparison, might have feeds from blogs about design, travel, sex and food all sandwiched together.

Tumblr could play with the idea of promoted posts or tags, much as Twitter has done. But Mr. Sabet believes it will pursue its own path. "At a certain base level, what you're selling to advertisers is engagement, and Tumblr has that in spades. I think as Tumblr matures you'll see them follow these other large networks and create their own kind of data center, their own breed of ad products."

The gang as it once was (via Technology Review)

Venture capitalists have come down with a bout of  seriously itchy feet. Just this week, we heard Union Square Ventures was raising a new fund, we broke the news that Andy Weissman was leaving betaworks for UVS,  Polaris Venture Partners' Mike Hirshland announced he was leaving the Boston fund to launch a new seed firm, and today AllThingsD's Peter Kafka reports that Twitter will lose Fred Wilson (one of its earliest backers) and Bijan Sabet from its board by the end of the month.

According to Mr. Kafka's sources, "there's no bad blood behind the move." Over time, the board had swelled to include Flipboard’s Mike McCue, former DoubleClick CEO David Rosenblatt and ubiquitous Valley Peter Currie along with Benchmark’s Peter Fenton and CEO Dick Costolo. In fact, the company will not be filling Mr. Wilson's and Mr. Sabet's soon-to-be empty seats. That leaves Twitter, which has seen a number of executive unrest over the years, a "little less unwieldy."

Both Mr. Wilson's fund, Union Square Ventures, and Mr. Sabet's fund, Spark Capital, have sold some of their holdings in Twitter, which is now valued at $8.4 billion, via the secondary market, but "continue to hold a majority of their stakes," reports Mr. Kafka.

Via Twitter, Fortune's Dan Primack proffered an explanation for their departure, tweeting, "twitter board shakeup reflected in who was offered cash-out on last VC round." According to Mr. Primack, while "no one cashed out entirely," only some investors, including USV and Spark were given the "option of cashing out," while others like Benchmark and Insight weren't. He says "the option was just to sell up to (approx.) 20% of stakes," although what percentage they exercised is still unknown.

Help me help you.

Betabeat has already documented the phenomenon of VCs forgoing the usual pitch process and urging you to steal their ideas instead. Spark Capital's Bijan Sabet didn't go that far. But wantrepreneurs with innovator's block might want to take note of a post on his Tumblr this morning where he suggested that the proliferation of consumer electronics devices, the "multiple floating iPads" around Mr. Sabet's home, could really use a way to distinguish between multiple users.

Take our beloved Sonos for example.

I now have Twitter and Spotify connected to our Sonos system. It’s very cool.

But our entire family uses Sonos--not just me. So any songs that are starred in Spotify on Sonos will show up in my profile. And if someone wants to tweet a song, that will come from my @bijan account. So if you happen to see a “listening to Rihanna” tweet from my account, just know that it wasn’t me ! :)

As more and more of our devices are able to tweet and offer personalization, we need some sort of way to do multi-user profiles. Sounds straightforward enough but the challenge will be making it beautiful, fast and simple.

If you follow Mr. Sabet's Tumblr, you'd know just how badly the indie rock fiend would hate for anyone to think he's bopping along to Rihanna.