One possible way to put this to use could be for a instagram powered tumblr. During your daily life you're taking pictures with your phone and pushing those photos to a blog. Maybe you have an interesting lifestyle that lends itself to marketing & promotion. If you're meeting with musicians, reviewing hiking gear, or even traveling, you might find a way to give people more information about what you're seeing and doing while adding a monetization stream to your blog.
The Taggstar API allows for control over how the little pink stars appear on your images. With it, you can enable or disable the Taggstar UI for individual images. You can even check to see if any images have updated stars on demand. The one big missing feature is styling for the stars. Clearly not everyone will love pink and white stars all up on their blog. How about some choices in icons and colors? Skulls, kittens, dollar signs, anyone?