As for the song, it has huge potential to smash. Obviously a super catchy song made for Top 40 radio... if the label supports it with a good radio deal it should 100% take off. Got to have faith in Interscope.
Only reason that I could see it not doing anything (other than not getting a radio deal), is being dismissed as "just the CMM" girl. But I'm looking at other artists with one huge hit and they all seem to make music that is more adult contemporary and none of their follow-ups fit Pop radio. The closest to Carly seems to be Vanessa Carleton, whose music after A Thousand Miles was more indie and and AC, whereas Carly is going right for Top 40.
Leave Justin alone, as much as I dislike him, he has fans with daddy's dollars who are willing to spend on whatever Justin says, so let him give Carly promo. If that means him calling her "his artist", then so be it!