I'm also unclear about what it's all about without signing up. Is the general idea that you can see people's reviews about products and keep a catalog of stuff you own and want?
Yup. For now, it combines a personal inventory, your wishlist , and various social features. The idea being that you can discover new products, share your tastes, and get higher quality reviews from the people you know.
I used to have a high fashion blog, and I would have probably found it valuable to curate my trending wishlists and to show off what I've bought and where from.
It's kind of like a clever way of showing off what you own without bragging
My wife works in fashion, she thinks it could be a great way for models to share their wardrobe for photoshoots.