Newspapers are on the decline, sure… but when it comes to subscription content sites, there’s a surge of innovation going on.

Seriously, with Newsweek going digital, the new Vimeo paywall, and now a whole new concept for the Houston Chronicle, it’s a paywall bonanza… Whether or not this surge will reverse the downward trend in online revenues and bring about a massive payday, well, that’s up in the air.

Paywalls, as you already know, are the one-size-fits-all, catchall solution for making money from online publications. To be fair, paywalls do seem to be working across a wide array of markets.

The interesting, and potentially frustrating thing for users, is that basically every single paywall is different. Google Wallet is developing a standardized paywall solution, but as it stands, paywalls are pretty confusing.

There a number of competing models, but one of the more innovative is the one recently adopted by the Houston Chronicle. What’s different about it is that it uses two different domains: HoustonChronicle.com (paid) and Chron.com (free).

Here’s what John T. O’Loughlin, president of the Houston Chronicle Media Group explains the move:

The new site is a complement to Chron.com, not a replacement. On Chron.com, you’ll find information on breaking news, weather, traffic, pop culture and news-to-use, such as events listings and city guides. HoustonChronicle.com will offer deep analysis, enterprise reporting, exclusive photos, and the work of your favorite columnists in business, sports, education, city and state government, and arts and culture, plus everything found in your daily newspaper.

This two-pronged approach is interesting, because it’s kind of an “all of the above” strategy that competes with itself in a way. Basically, it’s a split test…

On the one hand, you have the hard-hitting, prestigious news site that goes in-depth into the real news stories that may impact your life — that costs money. On the other, you have a light, fluffy pop culture site with breaking news blurbs — that’s free.

If you were an investor in the Houston Chronicle, which model would you bet on?

Other news organizations, like the New York Times, have been running with a more cohesive paywall strategy (which seems to be working). In the Houston Chronicle’s case, it will be very interesting to see which model is self sustaining.