Applications to publish photos online

Hi all :-) While looking for a new job, I couldn't keep my hands off the keyboard, so I've started a little project: an application to upload your photos to multiple online services at once (like 500px, flickr, facebook, etc.).
The functionality I plan to implement:

• Drag & drop photos from the file manager (or other applications)
• Select the services/sites where to upload the images to
• Optionally scale the images
• Decide what to do with metadata (title, description, tags, geolocation, people): keep / remove / edit
• Optionally select a watermark and position it (allowing different positions for each image)
• Add any site-specific options for each of the selected services
• Start the upload, show progress indicator
• Show clickable links to the uploaded photos for each service, so you can quickly go there and share/edit etc.
• The application would work on Linux, OS X and Windows.

My questions for you:

1. Would you use such a program?
2. Are there some more features which you see missing here and would need to be added?
3. What do you currently use to publish your photos online?
4. To how many public websites do you usually upload your photos to?

Please comment :-)