Joie Manda
President, Def Jam

The recently installed Def Jam prez packs his timeline with promotional tweets and retweets rooted in his label's stacked roster of marquee hip-hop artists, with the occasional plug for Island family artists like the Killers thrown in.

Larry Marcus
Managing Director, Walden Venture Capital

Larry Marcus' Twitter feed is exactly what you'd expect from a former equity research analyst and current investor in Pandora, BandPage and SoundHound: links to newsworthy and insightful reports on technology plus the occasional tweet about one of his investments.

Ron Mills
Music Programmer/Producer, Sirius XM

Mills is heavy in the mix and in the tweets. Follow the SiriusXM veteran and Queens native for a steady stream of hip-hop chatter and promotional tweets that shoot between the DJs and programmers driving the scene's sound at radio, satellite and elsewhere.

Mark Montgomery
Co-Founder, Echo Music

A Twitter feed chock-full of Foursquare check-ins tracing the efforts of Montgomery, a veteran of the e-commerce space (his earlier venture, echo, sold to IAC/Ticketmaster in 2007), to turn Nashville into a hub of digital music innovation through his new incubator-like project, Flo.

Brendan Moore
Product Manager, Frontgate Tickets

Moore is a smart digital marketing techie who is working to integrate marketing campaigns with Web and social media development. Sample tweet: "I think everyone saw this coming: BandPage Unshackles from Facebook, Now Helps Musicians Build Sites and Widgets"

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Todd Moscowitz
CEO, Warner Bros. Records

Not a heavy tweeter (by Twitter standards), but when he is posting, expect a strong dose of oddball humor with a few WBR promotional tweets thrown in, as well as a running commentary on his conversations with his cat.

Mark Mulligan
Digital Media Analyst/Consultant

A self-described "music industry bigmouth," Mulligan tweets with 15 years of research management experience from across the pond. His stream is rife with links to industry news and packed with dialogue with fellow opinionated industry watchers.

David Noël
Community Manager, SoundCloud

With a job description that includes getting people excited about SoundCloud, Noël has taken his role to heart. He tweets links to new tunes and new opportunities at the social music hub, interacting with other users of the service along the way.

Brian O'Connell
Promoter, Live Nation

Dialogues with die-hard country fans and tweets of the latest news from Nashville, all while working with Rascal Flatts, Toby Keith, Brad Paisley, Sugarland and more. In response to a British fan begging for more Nashville acts to come to the United Kingdom, O'Connell quipped: "Need a bridge, we like our busses."

Frank Ocean

His tweets are like his music: cryptic, soulful, intelligent and wry. Sample tweet: "getting blacklisted by major retailers and still selling a lot of albums is a great feeling. thanks yall."