I came across Drop.io recently. Like so many of the things I love on the web (can you say Twitter?), it's neat but I'm not entirely sure what I am going to do with it.
Drop.io is, in essence, a really easy to use file sharing site. You can create a Drop.io drop site without registering or even setting a password. Instantly, you'll get a little corner of the web where you can upload files, notes or links -- either to store or to transfer to somebody else. Once the data is uploaded, all you need to do is tell somebody else where to find it (www.drop.io/YOURACCOUNT) and they can head off to grab it.
There are a lot of file transfer sites out there, but two things set Drop.io apart: first, it is the most hassle-free web 2.0 experience I have had in a long time. Second, you can add content to the site by uploading, by sending an email or even by leaving a voicemail. That's pretty cool.
Check it out, and if you come up with some interesting application of Drop.io, shoot me an email and let me know.