The massive interest in Facebook is due, first of all, to its social appeal. The apparent thrill of in-your-home socializing with as many people as you want, keeps users coming back for more. Millions of users are now accessing the site via mobile device, which adds up to countless hours spent on the network. Job-seekers, too are a growing contingency, as Facebook gives them one more forum on which to market their skills.

The news comes at the same time Facebook’s user population crashes through the quarter-billion barrier. Independent studies confirm that Facebook is more popular than Twitter, MySpace, Digg, and any other social networking site, combined. That’s an impressive feather to have your hat.

While numbers are fun to look at, such statistics may cause employer’s concern. More and more IT managers and bosses are putting the kibosh on Facebook, hoping to keep social-happy employees from squandering away company time by checking their friends’ status updates. To circumvent filters or regulations, many employees simply log on using their phones.

Newly plugged-in retirees and the above-55 crowd may also be thanked for their contribution to the ballooning popularity of Facebook. A recent rise in the baby boomer generation on Facebook has given the social networking site a new more mature cast.

The Baby Boomer Facebook boom is not the only interesting fact. Add to that the significant decline (16.5%) in high schoolers, plus the 21.7% slide in collegians, and you have a puzzle worth mulling over. Are young people leaving Facebook?

Why?

Some conjecture that the “social-networking giant has morphed into a virtual parlor for the middle-aged.” After all, the 35-50s demographic represents more than a quarter of all Facebook users-a sizeable slice by anyone’s terms. Perhaps it’s because Facebook is now a place for job seekers and entrepreneurs rather than teens looking to connect.

But others dismiss the numbers with a wave of their hand. Sure the percentage figures mark a slide in “high school” and “college” attendees, but what does that say? According to one Facebook philosopher, “The data is based on which Facebook users choose to identify the school they attend on their profile pages.” With graduation just a month or so behind us, “millions of young peopledrop[ped] online affiliations with their alma maters.”

The data farm itself, istrategylabs, calls it “the most troubling statitics [sic]” and points to “rumors that these younger user groups are being aliented [sic] by their parents joining the service.”

Privacy concerns, parental fleeing, or just a graying Facebook population, the statistics do give users something to think about. Maybe you should post it on your status.