Sinnreich currently serves as Managing Partner of Radar Research, a media and technology consultancy, and is a Visiting Professor at New York University's department of Media, Communication and Culture. He has also written about music and the media industry for publications including The New York Times, Billboard, Wired News, Truthdig and American Quarterly. As a Senior Analyst at Jupiter Research in New York for over five years (1997-2002), he produced research covering the online music and media industries and provided hands-on strategic consulting to companies ranging from Time Warner to Microsoft to Heineken.

He has appeared on ABC World News Tonight, The CBS Early Show with Bryant Gumbel, NBC's Today Show, CNN, CNBC, BBC Radio and Fuji TV. He has also addressed several university audiences and professional organizations, including Fordham University, University of Amsterdam, Technical University of Munich, and The New York State Bar Association. He has also served as an expert witness in several court cases, including the recent Supreme Court file sharing suit MGM v. Grokster.

Sinnreich also writes and performs music, as bassist for artists and groups including seminal ska-punk band Agent 99 (Shanachie Records) dancehall reggae queen Ari-Up (lead singer of The Slits), and Tony award-winner Trazana Beverly, and as a co-founder of NYC soul group Brave New Girl, jazz band MK4, and LA dub-and-bass band Dubistry. Two of the songs he composed for Brave New Girl have been licensed to MTV's animated series, Daria, and a song he wrote for Dubistry was recently featured in the award-winning short film Life As You Know It, directed by Kristina Robbins-Higgins for Audi Films.