It is everywhere…that green ShareThis button, that is. It is a clever little script that allows web surfers to share web pages, blog posts and even videos with their friends, or on social media sites.

And now Nextumi, the company behind ShareThis, has raised $15 million in Series B funding from Draper Fisher Jurvetson and a bunch of other VCs. The company had raised $6 million in Series A funding, bringing the total to $21 million. The $15 million investment seems a tad excessive, and makes one wonder about the valuation being accorded to this company. Or perhaps it is the sign of the times, as venture capitalists dole out cash by the bucketful.

ShareThis is the brainchild of Alex King, a well-known developer in the WordPress community. Tim Schigel, who was a partner at Blue Chip Venture Company, led the initial investment in the company and liked it so much that he became the CEO of the Dublin, Ohio-based company. I met with them back in November, just when they were about to roll out their product.

I had a wide-ranging conversation with them, and got a glimpse at their plans for ShareThis. If you have seen ShareThis in action, it does occupy premium real estate on some of the top blogs. Analytics, targeted advertising and contextual matching were some of the ideas they discussed, though I am sure their plans have evolved since then.

My guess is that they are going to be focused on low-hanging fruit, that is advertising, In January, the company claimed that it has 26 million unique users and 100 million page views. If they have sustained their self-proclaimed growth rate of “50 percent every month,” then that business model makes sense. Of course, how many people will see the ads and act upon them is a whole different dilemma — the one that has everyone from Facebook to MySpace confounded.