It's gonna be really hard to score #1 debuts now. If you add airplay and sales only Bieber is easily #1 but fun.'s streaming must be huge. This could affect Britney and GaGa's future lead singles if they are against a song that is huge in streaming too.
Honestly, it's better this way. Only songs that are undeniably massive and more accessible will top the Hot 100. The more difficult, the better.