Over a six-season run that ends Monday (8 p.m., The CW), “Gossip Girl” was a teen drama known for its love triangles, scandalous affairs, OMG moments, and lots of very bad behavior by very rich people.

It also became a prime example of how a little show can make a big splash in today’s fragmented TV landscape.

Despite what you may have heard, “Gossip Girl” was never a huge hit. Not even close. At least not in the way we typically measure big hits — via audience size and mass popularity.

The series, in fact, drew an average audience of only 2.4 million in its first season on The CW and ranked 150th out of television’s prime-time shows. For comparison’s sake, “American Idol” that season (2007) averaged more than 30 million viewers. Now, that’s a hit. (Incidentally, the “Gossip Girl” audience this season has fallen to under 1 million.)

Had “Gossip Girl” aired on any broadcast network other than The CW, its fans wouldn’t be spending this week looking forward to an apparent wedding between Blair (Leighton Meester) and Chuck (Ed Westwick) and the long-awaited revelation of mysterious blogger Gossip Girl’s identity. That’s because the show would have been killed off in a matter of weeks.

But The CW was and is a niche network that, like many cable channels, is able to make do with smaller audiences. What would be a bottom-feeding series somewhere else can be a big fish there.

Moreover, it’s significant that “Gossip Girl” came along when the still-fledgling CW was struggling to fend off extinction. The network was desperate for a show – any show – that could build some buzz. A show that could define its brand.

“Gossip Girl” was that show – a new-media offering that fed off a kind of hype that far exceeded its ratings and managed to achieve substantial pop cultural cachet despite its lack of vast mainstream appeal. How? Here are a few factors:

• The show was based in and shot in New York. Like it or not, everything seems to matter more when it happens there.

•  The viewers who did watch – teens and young adults – are among those most coveted by advertisers and the youth-obsessed entertainment media.

•  Its influence transcended the TV screen. As with “Sex and the City,” young females didn’t just want to watch it, they wanted to live it. (The show inspired its own fashion line.)

• Flashy and trashy, “Gossip Girl” generated controversy while positioning itself as forbidden fruit for teens. A watchdog group famously labeled the show as “every parent’s nightmare.” Instead of running from the criticism, The CW openly embraced it with an irreverent advertising campaign, which, of course, generated even more attention.

That’s basically why a very lightly watched show was able to land its attractive stars on so many magazine covers and why those stars – mostly notably Serena’s Blake Lively — soared to fame. And that’s why the show lived long enough to be honored with a fawning retrospective Monday night and leave its fans with a heartfelt XOXO.