Gravatar
How many services do you use today which has a profile picture for you? Do you wish you had a global universal profile picture, which can be changed in one place and kept up to date easily? Or just that you do not need to keep uploading one every time you sign up?
Gravatar is a service which offers exactly that! A single place to have your profile image which then can be used in many places. You can have a different image per email and put an age rating on the image too which lets you also share different experiences based on where. And it is totally free ??
For developers, it is easy to integrate it - have the email and you get most of the URL for the profile image - it really should be the default for every service!
Gravatar has also joined the Link-Forest idea (along with LinkTree, and Bit.ly Pages) - Gravatar has a really nicely built version, which includes a lot of options and validation support. You can see mine at gravatar.com/robertjohnmaclean
Finally since it is my birthday - here is how I have changed in profile picture over the years. Thanks to Gravatar keeping all my profile pictures