SAN FRANCISCO — The year's biggest hits on the Internet's top video channel were anchored by an improbable singing sensation, a groggy boy nursing a sore mouth, a bride and groom dancing down the wedding aisle, supernatural heartthrobs and roller-skating babies. The eclectic cast of characters starring in YouTube's most-watched videos of 2009 served as a reminder of the quirky appeal of a Web site that accepts about 20 hours of new video every minute. The list released Wednesday marks the first time that YouTube has ranked its most-watched videos in any year since its 2005 inception. YouTube's 2009 star was Susan Boyle, the frumpy Scottish woman who mesmerized the world with a heartwarming rendition of "I Dreamed A Dream" on a British talent show in April. Boyle, now 48, ended up taking second place in that competition, but no one came close to outshining her on YouTube.