On Stumbleupon, when I search my interests, usually crafts, I am taken to site after site of blogs and websites that are dedicated to crafting. They are typically sites that I would not have found otherwise, but have wonderful ideas.
Pinterest shows pins, or images of things found on the web and wanted to share with others. Once again, I usually look at the DIY section and find pictures of projects and ideas others have made. Clicking on an image can bring you to a blog or website and often shows you how to make it too. You can also do a search to find examples of whatever you are interested in. For instance, during Halloween I was looking for costume ideas and found a number of handmade costumes to get the inspiration flowing for my costume.
On each website, you can keep track of your favorite sites or ideas so you can easily go back to them. This has always been the most frustrating part of exploring the internet for me. I constantly wander from what I was originally looking for and want to remember the names and addresses of all the wonderful new sites I discover. Both stumbleupon.com and pinterest.com help me keep organized.