How much they contribute to the show and thus how many discussions they create amongst the fans on forums, social media, BOTS and in real life. The most talked about housemates are - with a few exceptions to allow for unjustifiable housemates like Jade in CBB5 to be discounted - the most entertaining since debate is what keeps shows like this afloat.
The stars of the show this year have been Helen, Ashleigh, Steven, Mark

as well as Danielle and Christopher and then to a lesser extent Toya and Pauline. The rest had their moments (Biancca, Matthew, Marlon, Winston), were supporting characters (Chris, Jale, Ash, Kimberly) or were fodder (Pav, Zoe, Tamara)