[Mac Hiavellian]

It's always been targeted at a youngish audience because once upon a time it strongly encouraged you to vote via text and recieve instant text updates and the HMs were generally in their 20s and 30s. But the audience type has changed because:

1) The original audience aren't as young as they once were and over the years more younger viewers come along so it appeals more so to newer teen viewers
2) The emergance of new media technology e.g. Facebook, Twitter and YouTube have replaced the text alerts which were the 'now' back in the day
3) the emergance of fresher and edited reality shows such as TOWIE has influenced the style, editing and appeal of BB so it's had to follow this trend to keep fresh

EDIT: It's worth noting that while regular BB tries to appeal largely to a young audience to stay 'cool', Celeb BB still appeals to the slightly older fans because you notice most of the time the celebs are older than the bunch in the regular series although this year's perhaps got the yougnest group of celebs to date and also CBB gets more media interest becaus eof the lineup speculation