Pinterest is visually pleasing site for collecting photos and links to stuff you like and sharing them with others. While there are tons of other options for social bookmarking (e.g. Digg and Reddit), Pinterest's visually pleasing interface has made it a great hit.
The site is currently still invite-only, but you can spend hours browsing what others have pinned. You can use Pinterest to look for gift ideas or just browse photos and videos in different categories, including architecture, food, humour, clothes and technology.
Once you sign up and get an invite, start pinning things to your boards. By default, your five boards will collect favourite places, home items, products, style and books -- but these are editable and also sharable so others can contribute as well. There's a Pin It bookmarklet and an iPhone app to make pinning everywhere easy.
If you like creating inspiring bulletin boards (or looking at them), check out Pinterest.