The announcement characterized the deal as funding for the WidgetBucks ad network, not Mpire, which is sort of fading into the background as the parent company.

No wonder, since its WidgetBucks ad widget went from zero to 5 billion ad impressions in just its first eight months, and nobody can afford to compete with Microsoft's Cashback program.

The new funding will be used to develop three things, the company said in its release: "technology to further optimize publisher earnings, global expansion to diversify publisher revenue, and team development to extend the company's engineering, sales and marketing efforts."

From DFJ partner Bill Bryant's comment in the release: "While the recent growth has been phenomenal, what we invested in is the promise to truly transform performance-based advertising for publishers."

I wonder if it's also betting that WidgetBucks will be snapped up soon by one of the big ad players wanting to be sure they have great widget tools in the full menu of services they can offer publishers.

Here's an example of one of its widgets that publishers and bloggers can ad (no pun intended ...) to their sites, this one with an iPhone skin: