If you directly run Quick Snap, it behaves like a simple camera app and saves photos to your phone's Camera folder. There are no filters/effects or photo editing tools. There is an experimental feature to disable the camera shutter sound, but this may not work on all phones.
If you would like to apply effects to your photos & share them online, then you can use QuickSnap with the Lightbox app (see "More from developer" section).
When you run Lightbox, go to the Settings page and tap on "Clear default camera." The next time you take a photo with Lightbox, you will be presented with QuickSnap as one of the camera choices.
If you have any questions, please go to http://feedback.lightbox.com