The problem with most MP3 blogs is that they either make no attempt at all to provide critical insight along with their free music, or they inundate you with twee, narcissistic ramblings that make you wish you hadn't complained about that first group in the first place. A rare and splendid exception is the mighty paperthinwalls.com, run by Voice contributor and Brooklyn denizen Christopher R. Weingarten, which offers a minimum of three new tracks a day, but accompanied by actual commentary, artist interviews, benevolently snarky newswire links, and other stylish ephemera. Best yet is their new "So, Tell Us a Story" feature, written entirely by a musical luminary: You will learn, for example, about the profoundly unsanitary conditions aboard Twista's tour bus. Thank God someone is teaching the indie kids to read again.