Pinterest is not just about photo sharing! It's about idea sharing! Most of the photos on there are linked to a website where it will show you how to buy or make the product it's showing.
There are a ton of different things on there. Fashion styles, cosmotology trends, recipes, gardening tips, home improvement, DIY crafts, you name it!
You repin what you like back to your page, and it becomes like your own personal online "dream board".
Like JThomp42 said, you can also put your hubs on there!