Now's the time of year for everyone (including Billboard) to serve up their "Best of 2009" lists. Digital music services are no different, with iTunes, YouTube, and others all sharing details on what content stood above the rest for the year.

Susan Boyle's debut on Britain's Got Talent was YouTube's most-watched video of the year with 120 million views, more than three times as many as the second-place finisher, "David After Dentist." The "JK Wedding Entrance Dance" featuring Chris Brown's "Forever" ranked third with 33 million views.

Among "official" music videos, Pitbull's "I Know You Want Me" ranked first with more than 82 million streams. Miley Cyrus places second and third with "The Climb" and "Party in the U.S.A.," respectively, The Lonely Island's "I'm on a Boat" ranked fourth, and Keri Hilson's "Knock You Down" took the fifth spot. meanwhile touts Lady Gaga as its No. 1 artist, with "The Fame" generating more than 18 million Scrobbles by users. The rest of the top five is rounded out by the Killers, Lily Allen, the Prodigy and Franz Ferdinand.

iTunes last week revealed its top-selling songs and albums. The singles list was led by the Black Eyed Peas' "Boom Boom Pow"; followed by "Right Round" by Flo Rida; "Poker Face" by Lady Gaga; "I Gotta Feeling," also by the Black Eyed Peas; and "Gives You Hell" from All-American Rejects.

Top albums consisted of "Only by the Night" by Kings of Leon, the soundtrack to "Twilight," Lady Gaga's "The Fame," "Fearless" by Taylor Swift, and "Big Whiskey and the GrooGrux King" by the Dave Mathews Band.

As for Twitter, Michael Jackson led the top trending people list, followed by Boyle and Adam Lambert. Brown ranked fifth. It didn't have a specific music category. Meanwhile "American Idol" led the TV show category, followed by "Glee." The top hashtag was #musicmonday, while #sxsw was third.