Most people only know Match Group as the owner of some of the largest dating apps and websites, such as Match.com and Tinder.

But it's also the owner of Princeton Review, the popular test prep and tutoring service, after acquiring the company last year. The acquisition was done under Tutor.com, another educational site owned by Match Group.

If you haven't been following Match Group too closely, you'd probably be asking why a company dedicated to dating services would want to also run an educational service.

For those wondering, Match Group explained it a bit in its S1, which was filed Friday as it gears up to go public soon.

Here's what it said:

We acquired this business because it relies on many of the same competencies as our dating business, such as paid customer acquisition, a combination of free and paid features, deep understanding of the lifetime values of customers, and strong expertise in user interface development. Substantially all of our revenue from our non-dating business, or non-dating revenue, is derived directly from our students.

It also provided some additional info around the revenue it's been generating, looped under a category called "non-dating."

In the first half of this year alone, non-dating revenue was $50.8 million, almost the same amount as what it generated in all of last year, which came in at $51.8 million. Its deferred revenue, or revenue it's scheduled to record once the service is delivered, was at $25.4 million in the first half of this year.

That's still only a tiny fraction of Match Group's overall revenue which was $483.8 million in the first six months of this year. Last year, the company reported $888.2 million, up 11% from last year's $803.1 million.

Regardless, it looks like Match Group might further expand to other non-dating areas in the future, as it stated in the S1:

Successful operation of these businesses depends in substantial part on a common set of competencies with our dating business, and we believe we can expand the portfolio of assets over which we can leverage our competencies beyond dating. It is possible that we may acquire other non-dating assets if they meet the relevant criteria and provide the right value creation opportunity."