This site and iPhone app are equal parts entertainment value and useful tool.
Here's how it works: snap a photo with your phone's camera and ask a question. QpixL connects to your Facebook page and Twitter stream, posting the photo and question to all of your friends. They can answer you via Twitter, Facebook, or the QpixL site, and you can opt to receive email notifications anytime someone responds to your question.
Since the service is based on photographs, I think it's perfect to use while shopping. I love taking photos of items I think I want (or even taking a shot from the dressing room to see how it looks) and asking friends their opinion, so this is an easy way to reach a ton of my friends at once.
The iPhone app is free, and available in the App Store.