Anderton's (a music retailer in the UK) has an enormously popular YouTube channel (1M subs) which is basically just them demoing their stock while shooting the breeze. It's 100% an advertisement, but it's the sort that most people (including myself, who otherwise hates ads) is fine with because you have to seek it out.
I'm a huge buff for music gear/tech. I love seeing the newest plugins, pedals, software. I actively seek it out. I know demos of products are effectively advertisements, but they are the right type of ads and aimed at a crowd that seeks info the right way and likely is a higher probability of making a purchase.
