Britney's new single has taken the charts by storm unlike any other in recent memory. The track has been #1 at iTunes since its debut last Tuesday, and Billboard reported that it's expected to surpass 400,000 copies sold.
At top 40 radio, the song has just exploded. It's currently #16 with 4618 spins, all of that a gain of course, making it the biggest 1-week spin gain I've ever seen. It's daily spin gain of 700+ is bigger than the weekly spin gain of all but the five fastest growing tracks.
Clearly it will top the Billboard Hot 100 this week, giving Britney her fourth #1 and second single to debut in the top spot.