Web design and development site Treehouse is gaining users. Users that are willing to pay at least $25 a month to build their skills.

Over the weekend, Treehouse surpassed 12,000 users. “That’s not just 12,000 folks signed up to an email list for free classes they don’t get much out of,” the company tells WebProNews. “That’s 12,000 students paying $25/month for access and regularly spending time learning.”

Treehouse does have videos that are free to watch, but only a small portion of them are free. “To learn from all of our courses, you need to pay $25 per month,” CEO Ryan Carson tells us.

Treehouse does have a couple of different plans. That’s the cheap one – the “Silver Membership”. There’s also a “Gold Membership,” for $49 a month with some additional perks.

Treehouse offers courses in web design, web development and iOS development. Carson says the interest in web design is greater than both of the others.

On the advantages and challenges of developing for iOS versus the web, Carson says, “The advantage of iOS is that there is a huge app economy in the Apple App Store and the Android App Store. It’s a brand new channel to customers that was untapped before. The disadvantage to iOS apps are that the iteration cycle is much slower as each time you change the app, you have to re-submit it to the app store, wait for approval and then it goes live.”

There are plans to add Android developer training. In fact, it will be going live in a few weeks, Carson says.

Treehouse will also soon launch courses in PHP, WordPress, jQuery and some other unnamed areas. Without getting into specifics, he says they’re also going to make learning more fun.