While Wetpaint’s $25 million new round of funding was leaked to one and all under embargo until 12:01 am EST today–including BoomTown, so don’t assume any of us report our little hearts out on all these bits of news–what the press release did not disclose, sources said, was an intriguing new investor: Fidelity Investments.

What’s interesting about this wrinkle is that it is yet another validation in the Web 2.0 world from a large traditional institutional investor.

Fidelity, with T. Rowe Price, already plunked down big bucks to invest in widget king Slide in January.

Seattle-based Wetpaint, which allows users to make wikis and social-networking sites easily, has raised about $40 million in total so far. New investor DAG Ventures led the current round, which included investors from two previous rounds (Frazier Technology Ventures, Trinity Ventures and Accel Partners).

BoomTown could not determine exactly how much Fidelity kicked in to Wetpaint in this round, although it did pony up almost half the new $50 million Slide investment.

Wetpaint, which also announced a new embeddable product called Wetpaint Injected today that sounds cool, says it will use the additional funds to goose its collaborative–or as we like to call it: wikified–social publishing platform.