Sangria MN is a good place for reaching a certain demography - I saw CH's coming here is a bit like doing an instore meet&greet, probably prompted by a software that tracks her social media mentions. It's purpose was to strengthen her personal brand and name recognition. A stronger personal brand and a bigger number of followers gets you lots of things, including paid contracts. What trades hands is our trust in her. If she recommends something, a certain percentage of her followers will buy that blind, and that has definite monetary value. Very few people do publicity without a specific agenda.
I find it easier to read blogs that have a clear agenda. Pocket Derm promotes teledermatology and their subscription cosmetic retinoid etc products - fair enough, they are never going to say that isotretinoin is bad for you. Paula promotes her products and dismisses many others - she could be better about disclosure though, Beautypedia is made to look impartial but of course it is not, they will never say that Paula's Choice products are total rubbish, and they have chose the product evaluation criteria specifically to make their offerings look good. Beauty Brains people formulate hair products for their living, it is not in their interest to make Unilever go bankrupt but as they have lots of potential employers, they can freely say that salon products are a bit of a con. However, they are unlikely to become no-poo campaigners or natural skincare advocates and won't organize an anti-globalization riot 
It's the undisclosed stuff makes me uncomfortable - it's money under the table, and I might be footing the bill. I think the key question is to ask, who will benefit and in what way if I read this, buy this, or click this link?
I think there is some research that says that people are not particularly good at seeing their personal conflicts of interest. That means that CH might see her trip to LA as a fair exchange of services (a small compensation for years of unpaid collaboration with Pixi). Someone else might see her as a paid consultant who was hired to generate positive publicity for the brand and to strengthen its social media presence. So people may genuinely believe that they remain impartial despite financial or other ties... 