For those who like to share pics with their Windows Phone, you have your MMS, Facebook, SkyDrive and...well, email we suppose. But most of those involve direct sharing of the photo as oppose to giving a link out which would allow you to share the single photo multiple times over different protocols at varying times.
Imgur (pronounced image-er) is a popular and free photo sharing site, used heavily with Reddit users (see Alien News for WP7) and is known for its sharp, minimalist design and anonymity (it strips photo meta-data off automatically). Developer John Sprunger has made a free app, appropriately called Imgur Photo Uploader which not only allows you to upload any pic on your phone, but share the photo link with numerous sites including: Facebook, Twitter, Reddit, DIGG, email, and SMS. Imgur links are short and concise e.g. http://imgur.com/WsCdz.jpg making them ideal for sharing. Plus it saves your uploads for later use, right on the device.