Triple A radio is producing some major-league hits.

The niche format (whose nickname is short for "adult album alternative") fostered the top Billboard Hot 100 title of 2011, Adele's "Rolling in the Deep." The song spent 14 weeks at No. 1 on the Nielsen BDS-based Triple A chart-the first ranking on which it appeared before crossing to pop, adult and even R&B and Latin radio.

Triple A also championed Gotye's "Somebody That I Used to Know" (featuring Kimbra), which earlier this year led triple A for 13 weeks and the Hot 100 for eight. On Nielsen SoundScan's recently released midyear sales tallies, Gotye's smash earned top-selling digital song honors (5.5 million downloads), while Adele's 21 extended its reign, claiming the top-selling album crown for the first half of 2012 (3.7 million units).

The success of "Somebody" especially underscores the format's swelling acceptance of new artists. The song's triple A command began an active 22-week streak of artists reigning during their first visits to the survey. Following "Somebody," Of Monsters and Men's "Little Talks" led for four weeks and Alabama Shakes' "Hold On" ruled for one. As of this issue, the Lumineers' "Ho Hey" has spent four weeks on top. Since the chart launched the week of Jan. 20, 1996, never before had four rookie acts reached No. 1 consecutively.

Other debuts finding success at the format include Imagine Dragons' "It's Time" (at No. 2 this week), Ed Sheeran's "The A Team" (No. 4) and Grouplove's "Tongue Tied" (No. 5).

The domination of fresh blood at triple A challenges the format's reputation as a haven for veteran rock acts. Just one artist appears on this week's triple A ranking whose Billboard chart history predates the '90s: Bonnie Raitt. A year ago, there were three (Paul Simon, Lenny Kravitz, the Cars). Five years ago, there were five.

Why a more favorable reception of somebodies that we previously didn't know? Cumulus San Francisco director of FM programming Dennis Constantine, who oversees triple A KFOG, credits the impact of the digital era on consumer behavior in aiding new artists' growth. "More people are buying downloads of individual songs than buying a full album. So we're finding new, creative songs from unknown artists."

Triple A programmers and label promotion executives cite social media as helping demystify new artists. "The Internet, mobile phones, Facebook and Twitter have accelerated familiarity to listeners who use these portals for music discovery," says Lauren MacLeash, PD of Clear Channel's KTCZ Minneapolis.

Social media has buoyed promotion of Sheeran's debut. "We could only get Ed to Nashville on a Monday and all the major venues there were sold out," Atlantic Records director of triple A promotion Brian Corona recalls. "With [Tuned In-owned] WRLT's relationship with 3rd and Lindsley Bar and Grill, we were able to schedule a 6 p.m. showcase. Through social media messaging, when we arrived at sound check at 3, there were already more than 200 people there."

The popularity of multi-artist festivals also plays into triple A's riches of new talent. This year's South by Southwest "was huge for the Lumineers," says Dualtone director of promotions Lori Kampa, who afterward attended some of the group's first headlining shows and "fans were singing along to almost every word." Citing synchs including "American Idol," she adds that when Dualtone began promoting "Ho Hey" to radio, awareness of the group was already high. "It was a record that made sense for programmers to step out on because we had built amazing success that continued to grow."

Chris Mays, PD of Alpha Broadcasting's KINK Portland, Ore., muses that at its best, triple A is a "balancing act" of the best new artists and old favorites: "How can you resist playing the Black Keys alongside a classic Rolling Stones song?"

MacLeash says the success of triple A's newer acts ultimately promises benefits going forward. ""Adele, Gotye, Jason Mraz and others being accepted by top 40 means that the young end is into the new music we play," she says. "Long term, that's so important to our survival."