Mac: You don't need anything other than a browser to use minimalist file sharing app Fyels. However, if you are a Mac user, there's now an app version of the site available.
The basic concept and look of the app is exactly the same as the site: drag a file onto it and it will be uploaded, then you'll be presented with a shortened URL to share with anyone you wish.
Whichever version you use, Fyels now supports uploads of up to 9GB, and supplies a deletion password so you can get rid of files when you don't want them. This is automatically generated in the Mac app; site users need to supply an email address. The app is a free download for Mac OS X.