There are thousands of sites on the web which deal with music and you will find below the ones I really enjoy the most. This does not prevent you all to go to sites from music magazines (Mojo and NME in the UK, Paste in the US and Magic or les Inrocks in France), from bands or even from fans.
PITCHFORK : The n°1 reference (http://pitchfork.com/). A perfect music site, updated everyday, with the worldwide famous well-written and precise album reviews which rate from 0.0 to 10.0! Pitchfork tv page is highly recommended as well for exclusive films and videos.
ALLMUSIC : The Bible (http://www.allmusic.com/). Everything you want to know about a specific artist with a summary of his/her/their career and details of all his/her/their discography.
Favourite Podcasts (English & French-speaking – all available on iTunes)
SOUND OPINIONS : A great weekly show hosted by two excellent American critics (Jim & Greg): record reviews, state of the music industry, exclusive interviews, live sessions (Teenage Fanclub or Best Coast for instance in 2010), etc… One hour of absolute enjoyment. Thanks to our Chicago correspondent for the tip! http://www.soundopinions.org/
VERY GOOD TRIP : 4 shows per week from French novelist and rock reviewer Michka Assayas since summer 2016 on France Inter ; was there better news on French Radio this year? Probably not… His former radio show/podcast called Subjectif 21 on France Musique from 2008 to 2012 was already excellent but this one is even better as it gives 4 hours per week to its host to explore in detail a specific theme. First shows of 2016 on Alan Vega, Violent Femmes, Nick Cave, Leonard Cohen, the origins of hip-hop, Bruce Springsteen, etc… Ideal in the car, when running or cooking!