The Justin Bieber phenomenon can be explained in three words: YouTube, Usher and Twitter. The pint-sized Canadian singer was discovered through his YouTube channel, where he posted videos of himself covering R&B and pop hits and impressed one of the artists he covered, Usher. With Usher’s backing, Island Records signed the teenager and rushed him into the studio before puberty could set in, pairing him with the industry’s very best songwriters and producers to record sexless, tween-friendly alternatives to today’s glossy Top 40 hits. Bieber is a fine singer and dancer, but his true talent is social networking. He’s one of the biggest stars on Twitter, where his 2.3 million followers ensure he’s a permanent trending topic. He rewards the loyalty of his biggest fans by @-replying to them and re-tweeting their declarations of lovethe 2010 equivalent of signing an autograph.