what types of projects or products can anyone make using MARK.SPACE and with what browsers and programs can it work with

Its a marketplace inside a virtual world using VR, so, anything really, a shop for virtual goods, learning, social interaction, etc. there are a lot of things that can be created really, you could offer your services as a teacher, or as trainer, etc.
Maybe today the technology isn't as evolve as we would like but I think with time almost every product is possible to sell in their shops.