One of the things that makes the marketplace unique is the fact that you have no idea who you are buying from when you make a purchase. You have no idea what corp or player you are supporting by buying their products. This seems odd to me from the marketing angle. It seems like you would want people to buy your products and support you or your corp, but how can they do that if they don’t know who they are buying from. The only thing that drives sales on the marketplace is who has to lowest price, but as real life has shown us, some people are willing to pay more for the same thing, just because of brand loyalty.
I think it would be helpful to have the seller name and the sellers corp listed in the marketplace when they place sell orders, and same for buy orders.
I know there’s no difference in a item manufactured by one corp or another, so one corp isn’t going to make better Inferno Rockets than another, but the money they earn does support their activities and knowing who you are giving your ISK to is important when making those purchases if you plan on supporting certain corps in their growth.
To take advantage of branding you need to provide a different kind of service or product. Every item on a single market view is completely identical, and often in the same location as all the others. Except perhaps cutting off your nose to spite your face (paying more because you don’t like 0.01 ISK undercutters or something similar) or corp loyalty there’s few reasons to want to pay more than the minimum that couldn’t just be replaced by an ISK donation along with buying what you want at the lowest price. A brand is more than just a name next to your literally identical product. Yes, you ‘pay for the name’, but it’s because of the products or services that a name has produced that makes them able to sell based on their name. If you want to support someone then there’s much easier ways than buying stuff on the market from them, which only a minority of corps do anyway.
However, it is possible to do this in EVE too, it just works a little differently than you’re thinking. You can advertise your products and services on the forums or in chat channels; many have tried a shopping and delivery service combined, blueprints researched on demand, or leveraging their reputation as a trusted borrower or public figure to sell products. You can list your products on contracts where your name will be shown next to your products. You could even create your own website to peddle your wares.
Eve markets deal in fungible commodities and, in the larger markets, you’re often buying from station traders rather than the people who actually produced the product. It would be like asking the supermarket to label which farm each apple, carrot, etc… came from.
You can add value and establish a brand in Eve as described by @Elizabeth_Norn. I do that with with Capital BPC kits sold on contract and many people add value by building doctrine ships for their corp/alliance and offering them on contract.