Business Insider traffic is exploding – so what’s it worth now?

Back in March, Henry Blodget shared internal traffic data from Google Analytics indicating 7.8 million monthly uniques for his site for February, 2011. While Quantcast is apparently directly measuring BI traffic (it’s ‘Quantified’), that service indicates just 6 million visitors for March. So let’s assume the two metrics services use slightly different methods of measurement, with Quantcast running about 30% lower than Google (and assuming no significant change between February and March traffic). Here’s what Quantcast shows since then:

That’s some strong growth, and suggests internal numbers have risen to over 10 million monthly uniques. Where did this surge come from?

The strong stock market and lots of big biz stories certainly played a role, as did more distribution deals to portals, new site verticals and some organic growth from those catchy headlines. But more than anything, I think this figure on post volume from my Google Reader tells the story:

BI has massively ramped up its output, at least in terms of number of posts, if not word count. They’re doing 2,380 posts per week now, an average of 340 per day including weekends. Huffington Post, the editorial and business model BI most closely resembles, currently publishes about 2,500 posts per week (per Google Reader also). Like HuffPo, a good portion of the BI posts are from third party sources – either full article submissions/reposts or quick staff rehashes, often with little added value to the original save the curation and sexy headline. But in this business, sheer post volume does correlate to traffic, and when you have a vibrant community as BI now has, curation has editorial value.

What does this mean for BI revenues? We’d have to wait for Blodget’s next Full Monty update to know for sure, but if they did about $1.9m in Q4 on about 15m uniques, then even with a discount for some unsold inventory, in this strong online display market BI should be doing over $3m in quarterly ad revenue now, or over $1m monthly.

Anyone want to take a stab at valuation? Remember HuffPo sold to AOL in February at about $12 per monthly unique, about 10x the trailing year’s revenue, and about 5x expected revenue for the coming year. But it was growing even faster than BI at that time, unless BI’s growth over the past couple months can be sustained.