Apple has begun cracking down on unofficial sites that sell UDID activations to folks who aren’t registered Apple developers, letting them download and install iOS and OS X betas on their devices, a strict violation of Apple’s agreement with developers.

In fact, a developer’s $99 a year membership in the iOS Developer Program can be terminated if pre-release software is provided to non-authorized folks. Apple isn’t just revoking access to developers that sell UDIDs, it’s now going after sites that advertise UDID activations, filing DMCA requests to hosting firms.

As you can imagine, financial incentives outweigh risks and punishment involved. Savvy “entrepreneurs” have found the business of selling unauthorized access to iOS betas worth tens of thousands of dollars. You don’t need an office, staff, a telephone line or even a business name – just a small upfront investment, a web page advertising your “service” and spare time on your hands to get the word out…

MacStories editor Federico Viticci reached out to a bunch of sites that used to sell UDID activations, such as activatemyios.com, iosudidregistrations.com, activatemyudid.com, udidregistration.com and instantudidactivation.com, all infringing on Apple’s developer agreement.

Here’s what he found out:

While most of our emails bounced, we heard back from one of the site owners (who asked to remain anonymous), who confirmed his hosting provider took down the site after a complaint for copyright infringement by Apple.

Similarly, the CEO of Fused tweeted in a reply to Andy Baio that Apple had been “fairly heavy-handed” with DMCA requests to UDID-selling sites hosted on their network.

It’s a bit of a surprise then that the most popular site, udidactivation.com, was still doing business at post time.

Andy Baio is the author of an interesting Wired piece which exposed the underground world of selling access to Apple’s beta software to non-developers. With device activations lasting only a year and prices in the range of ten bucks per device, these sites turn eyebrow-raising profit, Baio explained:

For a small developer, unauthorized activations are a lucrative business that’s likely worth the risks. UDID Activation publishes their order queue on their official site, which shows more than 2,300 devices activated in the last week alone.

At $8.99 for each activation, that’s more than $20,600 in revenue, with $2,277 paid to Apple for the 23 developer accounts.

One site MacStories’ Viticci contacted has activated a whopping 19,000 unauthorized devices so far. Another guy told Viticci that their website made $75,000 since last June, when Apple released the first beta of iOS 6 to developers.

You must have noticed how Apple-focused sites’ comments (iDB’s, unfortunately, included) often gets trolled with shady accounts that advertise UDID “services”. And who could blame them: a bunch of people are eager to get their hands on software they’ve been reading about in news reports so clearly the market exists and demand is high.

If you paid for an UDID activation in order to test-drive iOS 6 betas, we’d love to hear about your experience down in the comments.