How does Facebook determine whom to suggest to you as friends in its "Find Friends" feature?

This topic probably does not quite fit under DU's "Computer Help and Support" group page, but I do not now where else to post it.

Facebook suggests to its users candidates for "Friends." For any given Facebook member, the means to most easily access the suggested "Friends" is to click the "Find Friends" button on the member's main page.

I find that the number of suggested friends appearing over the course of the past year has varied. About a year ago, the number of suggested friends was significant. Some of the suggested friends were friends of my friends. However many of them had no such common connection. I recognized a few of those suggestions as being residents in my town, but most of the suggested friends did not live nearby. Then, about six months ago, the list of suggested friends became confined strictly to friends of my friends. Now, in the past few days, the list of suggested friends has ballooned. Yes, still being suggested are friends of my friends. However, I am also getting many suggestions regarding Facebook members with whom I share no such common connection. Some of the suggested friends reside in foreign countries, this despite the fact that I have not contacted anyone from those countries.

From time to time, there appear articles which speculate about the algorhithms which Facebook employs to suggest friends to its members. I do not believe the far-flung theories mentioned in those articles. One such article was published a few days ago and appears at the following link.

http://gizmodo.com/facebook-figured-out-my-family-secrets-and-it-wont-tel-1797696163

In the article, the writer claims that a combination of data mining, facial recognition and other technology assists the workings of Facebook's "Find Friends" feature.

If you have any thoughts, I would be happy to hear from you.