Drop.io is an online collaboration and file sharing service. The free "drops" have 100MB limits, but you can purchase more space. 100MB is actually a lot of space. 30 lab reports only used 15 MB.
Drop.io allows users to have a simple, real-time, private online chat and share digital content (images, videos, documents and more). Each drop is non-searchable and non-indexed, can be password protected, and can even expire after a certain amount of time.
You can create a drop from the home page without creating an account or signing up. It is a very simple task and easy to use. You click on "Create a Drop" and then enter your email and they send you the link and password. That's it.
The "About" page on their site is actually a dropped document. It's interesting to see how they did it.
It is a very powerful, easy to use system. You can learn more about how to use it HERE.
I currently use it as a place for students to submit work to me without having to email it to me. I have placed a drop.io button on my classroom blog so the students can easily find it. I am just starting to explore the online chat and will also be using it to return students' electronic documents back to them with comments and grades. (you can also see the subscribe via email box on the class blog site. This site has assignments, due dates, resources and more and by subscribing to it, students get emails when ever I update the site) You can visit my Physics class blog site at: http://mrandradesphysics.blogspot.com/
Try it out.
UPDATE: Drop.io has been purchased by Facebook and is no longer available. Try out DROPitTOme as an alternative.