Three extremely simple Web services

The first day of class, we ask "what is a network-based application?"

Examples provide a partial answer -- a starting point. We do not want to be bogged down in details, so we want very simple examples. Here are three:

Eggtimer is a simple application where the program is stored on the network and downloaded each time it is used. Go to http://e.ggtimer.com/5 for a five-second timer or go to the home page for other options.

http://drop.io/ demonstrates an application in which the program and data are both on the network. With a couple of clicks, users can upload and share text, recordings, images, etc. Here is an example.

(Drop.io is surprisingly useful for such a simple application).

Aviary screen capture is a third example. You can capture and then edit any page on the Web by simply typing aviary.com/ in front of the http:// in the page URL.

For example, to capture the YouTube home page, you would enter:

aviary.com/http://www.youtube.com

Aviary automatically downloads the captured page image and an image editing program written in Javascript. Since Web clients contain Javascript interpreters, you can edit the page image when it gets to your computer.

Do you know of other network-based applications that are as simple to use and demonstrate as these?