Easy-to-use website builder SynthaSite unveiled a bunch of new features today that make it easier for users to blog and make money from their websites. Equally important, they also present new revenue opportunities for the San Francisco company.

From a business perspective, the most interesting addition may be the domain registration feature. SynthaSite, after all, offers its website building tools for free, as well as free sites under the synthasite.com domain. But what if users want their own domain name outside the SynthaSite umbrella? Until now, it was possible to set that up, but required a little extra configuration. Now, SynthaSite can set up a separate domain for you — for $14.95. Basically, SynthaSite is becoming a domain name reseller.

This sounds like a shift away from the business model that chief executive Vinny Lingham previously described. In past interviews, Lingham emphasized SynthaSite’s partnerships with other services like Picnik, Meebo and Widgetbox, rather than making money from its users directly. Now, he points out that domain reselling could be quite lucrative. He estimates that only between 1 and 5 percent of SynthaSite users will actually purchase a domain, but if the company eventually reaches, say, 20 million users (it anticipates crossing the 1-million-user mark by the end of the year), it could bring in multimillion-dollar revenues. Lingham is also open about the fact that SynthaSite (which competes with companies like Weebly) hasn’t completely figured out its revenue model yet.

“We’re lucky that our investors are open-minded,” he says. “We know we don’t know. We know how to monetize certain segments, but we don’t know what the final picture will be.”

Another new feature provides a way for both SynthaSite and its users to make money. Instead of just including a button for PayPal payments, users can now build a full PayPal store within SynthaSite. This should make it more feasible to build a small business website using the service — and of course, SynthaSite gets a cut of any purchase revenue. Greater integration with other services like Google Checkout could also happen in the future, Lingham says.

Finally, SynthaSite has built its own blogging tool. It lacks the number of options available with blog-focused services like WordPress, but it does offer an easy-to-use graphical interface and integration with the Disqus commenting tool. Plus it’s just an obvious addition — a personal website without a blog seems like only half a website to me.