It's well known in magazine publishing that putting a black woman on the cover of Elle, Vogue, Marie Claire and the like has an immediate and negative impact on sales, which is why it so rarely happens. The only possible exceptions these days (and they are not necessarily) might be Beyonce and Naomi Campbell; prior to them, it was virtually unheard of.

Furthermore, advertising (especially TV advertising) relies fundamentally on stereotypes, and to some extent it has to in order to get the message across in a crowded market - it's all about impact and memorability. So it matters to advertisers a lot exactly what and who is shown doing what. And if you buy any heavily-promoted major consumer branded product, you are buying into that process whether you like it or not. So at least know that. In a culture where we are both a numerical minority and pathologised, it is futile IMO to expect big-time advertisers to do anything other than what most currently do.

I'd say that 'African media' can sometimes bring a different set of problems (Pride, The Voice) but that's changing with the growing importance of the Internet as a marketing tool, especially for under-35s. There is plenty of potential to do good stuff, and it's happening - both for those who want to sell to our own, and for those who want to sell to everyone.