Barnes, a former arts and media correspondent for The Independent on Sunday and the Press Association, will lead an overhaul of the Qthemusic.com .
One of his first tasks will be to embed the Q Radio station into the site when it relaunches.
In the longer term he will work to revamp the content on the website so that it can be used seamlessly across Q magazine, radio and online.
Qthemusic.com will feature a listen-live radio player offering multi-platform streaming and scrolling text containing now-playing, programme information and studio messages.
Barnes will report to Q Magazine editor Paul Rees and Q Radio programme director Ric Blaxill. He joins Q from GCap Media where he was online editor for a year, responsible for launching and running TheJazz website.
His previous roles include seven years as the showbusiness, arts and media editor at the Press Association and three years at The Independent on Sunday as arts and media correspondent.
Rees said: "Anthony comes from a first-rate journalist background and his credentials make him an ideal candidate for the job."
Barnes said: "As a journalist and a music fan there can be no better destination than Q. I'm delighted to be joining at a time when the online site can play a crucial part in launching a great new radio station and acting as a unifier between the different platforms of the brand."
Q Radio currently exists as a jukebox-style digital radio station with 282,000 listeners a week distributed on Freeview, cable, satellite and online. At the time of the relaunch it will become available to listen to on DAB radio in London.
Its new line-up of presenters will include Acid Jazz records founder Eddie Piller, stand-up comic Russell Kane and former Xfm and BBC Two 'Desi DNA' presenter Samanthi.