Calameo is a new service for publishing documents from your computer to the Web. Like Scribd, it's dead simple to use, and will slurp up all sorts of documents of up to 100MB in size. What makes the service noteworthy is that you can take documents online and offline with a click of a button, without removing them entirely--which could be useful to business or education users who want to upload many items, then make them public at a later date.
Of course, the strong suit with any of these document-hosting services is the viewer. Calameo's iteration is not nearly as fast as Scribd's iPaper at the highest quality settings, but it does a fantastic job rendering intricate details on PDFs. Power users can dial down the quality on a sliding scale of 1-100, with the lower numbers loading faster, and being suited for simple text documents. Users navigate the pages with simple page turns, which pop up in the corner of each page. There are also simple arrows on each side of the screen, as well as a table of contents to jump around--fairly standard stuff for a Flash-based document reader, but it works nicely.
What I like about Calameo though, is that it follows your mouse around, and has a beautiful full screen presentation mode that makes documents a highly interactive experience without detracting from the content. Users can add video or audio clips to these documents as long as they have a direct URL to a FLV or MP3 file that's hosted elsewhere. This is partially where the service breaks down a bit in its ease of use. You'll have to venture off elsewhere to find that content and get it hosted. It's really not hard if you use services such as Box.net or DivShare to host your files, but I think Calameo is missing out on a great opportunity to roll the storage for those files in the same place when it's already hosting your files in the first place.
I've embedded a sample Calameo document below. Be sure to check it out in the full screen viewer to get the whole experience.