Seattle's Wetpaint said it is now attracting more than eight million unique visitors per month, a milestone that would give it an even bigger traffic base than Zillow.com. Of course, the audiences are quite different. Zillow focuses entirely on online real estate. Wetpaint operates a wiki platform of more than one million Web sites, ranging from fan sites for TV shows and sport teams to sites about technology gadgets and education.

In order to keep growing its user base, Wetpaint today also is introducing new features such as video galleries, enhanced discussion forums and embeddable widgets.

Last year, Wetpaint raised $25 million from Accel Partners, DAG Ventures, Trinity Ventures and others.

Some other Web site building tools have been in the news this week, with Seattle's DevHub launching a network of 55,000 sites on Tuesday and SynthaSite scoring $20 million in a second round funding.