LOS ANGELES - To measure the impact of "Glee" on pop music in 2010, just remember this: The misfits of McKinley High now have a place in the history books above the Fab Four.

In October, recordings by the show's cast overtook the Beatles in terms of the number of songs placed on the Billboard Hot 100. As of December, "Glee" now has 102 songs on the chart -- and with at least a season-and-a-half to go that has already been guaranteed by Fox, it's a safe bet that the cast recordings will give Elvis Presley a run for the top spot in the record books with 108 singles. The show has become a single-selling machine the likes of which Ed Sullivan could only dream about.

And much like "The Ed Sullivan Show," "Glee" has become the go-to platform for contemporary superstar acts with new songs to hawk. This wasn't necessarily the case when the show debuted in May 2009. The best-selling digital single for the program's first season was a version of Journey's "Don't Stop Believin'" that tallied 1 million total sales, according to Nielsen SoundScan. Now, halfway through year two, the season's top seller is a rendition of Katy Perry's "Teenage Dream," with 286,000 copies sold to date -- and it bested "Believin'" in first-week sales by 214,000 to 177,000.

The contrast in styles between the two songs -- one a decades-old standard with recurring pop culture resonance, the other a track that hit No. 1 on the Hot 100 in August -- exemplifies the show's push toward offering more current pop hits faster to its track-happy core 18-49 viewing demographic.

"In many ways, 'Glee' was built on classic hits," the show's music supervisor PJ Bloom says. "We needed cultural staples to grab a broad audience -- and it worked."

The trend toward top 40 fare certainly helps the show in terms of relevance -- tween viewers who are baffled by a reference to "A Chorus Line" feel like one of the cool kids when they can sing along to Bruno Mars' "Just the Way You Are." According to Fox, "Glee" is the No. 1 show in the 18-49 demographic among women, and the show's push toward pop is a targeted move to keep these viewers happy.

"Now that 'Glee' is 'Glee,'" Bloom says, "we have the latitude to explore newer songs on their way to becoming hits and the ability to add to the hitmaking machinery."

Other of-the-moment songs featured on "Glee" since its second-season debut in September include Travie McCoy's "Billionaire" and Cee Lo Green's cleaned-up "Forget You."

"This season we've really been put to task," Bloom says. "We're using songs on the show the same time they're charting as new hits. That leaves a small window for (show creator) Ryan (Murphy) and his creative team to choose the music and the production team to clear, record, rehearse, shoot, post and prep for retail. It's been as quick as a few weeks."

The development schedule for "Glee," according to co-creator Brad Falchuk, generally operates several weeks ahead of when the show airs. For instance, the week that the second season debuted, the cast was shooting the fifth episode of the season -- a tribute to "The Rocky Horror Picture Show" that eventually aired October 26 -- while Falchuk was writing the seventh episode of the season that aired November 16 and featured Gwyneth Paltrow as a Cee Lo-crooning substitute teacher.

To get the ball rolling as early as possible, Bloom says artists, labels and publishers are giving the show advance listens of upcoming releases as soon as they're comfortable sharing them. While this does help in the creative process, there's a downside. "These songs are often harder to clear because songwriter splits haven't been finalized or we precede a record company's ability to launch a campaign," Bloom says.

Adam Anders produces the songs for "Glee" and says he's even started working on songs before they've technically been cleared in order to keep up with the pace. "I beg and plead for titles, even as you're waiting for scripts to come out," he says. "I talk to PJ and say, 'What are the chances here?' It's like we're playing the odds on the songs."

And it takes Anders to complete production in order to move on to other aspects of the show -- like choreography for dance sequences. "There are so many moving parts to the show. You'll think you have four or five days, and then they can't get a location and they need it tomorrow," Anders says. "Obviously I'd prefer to have a week like we normally do for the songs, but we've learned to adjust on the fly and make it work."

Anders does believe that the quick turnaround is worth it, since pop songs hit the sweet spot with the audience. "The heart of 'Glee' is making people feel good," he says. "That's what popular music is there for. When you combine a great song with a great moment in the show, they take ownership of it and they want it."

The addition of Darren Criss -- who sang the show's cover of "Teenage Dream" -- as a cast regular and recurring guest stars like Charice also illustrate the show's push toward pop. "(Charice) came in, and it was a lovely meeting, and at the end her manager just had her sing a couple of bars of 'Gold Digger' and it was like, 'Oh, hold on a second,'" Falchuk says. "Oh, yeah, she's worth writing for." (In the season opener, besides doing Lady Gaga and Beyonce's "Telephone," Charice sang a blow-the-roof-off rendition of the latter's "Listen," and Falchuk says the intercut reactions of the "Glee" cast to her performance were all real. "It was a shock," he says. "She's 4 foot 2 and she can sing like that? Ridiculous.")

While the digital single sales are indicative of the show's popularity with the pop consumer, the track record of the compendium soundtracks proves that a diversity of genres is what drives album sales. The best-selling "Glee" soundtrack to date is "Glee: The Music, Volume 1," with 1 million in sales, according to Nielsen SoundScan, and contains tracks like Jazmine Sullivan's "Bust Your Windows," Neil Diamond's "Sweet Caroline" and "Defying Gravity" from the musical "Wicked."

Falchuk says he expects the show to keep on churning out several soundtracks per year -- and he expects the fans to keep buying them. "There's a reason why we put those songs together," he says. "The songs are there to take you on a journey, and we'd like to keep doing that."