thinkfree
The editing environment at thinkfree.com is astonishly similar to a desktop application's.

You can edit uploaded files, or you can start from scratch. Either way, the editing environment is surprisingly flexible and even allows some animations and slide transitions. Part of the secret is that ThinkFree is really a hybrid of desktop and web-based application. In order to get the full functionality of the "power edit," you will have to let ThinkFree install a Java applet on your local machine. For those cases when you may not want or be able to allow this installation, there's also a "quick edit" mode.
Once again, you have options for sharing a show. You can:
- Provide a link that will open your show in a ThinkFree window (with hideable Google ads). The interface offers a detailed outline of your slides, but the conversion seems less reliable than with Zoho or SlideShare. Personally, I care more about a reliable conversion than subtle features of the player.
- Embed a show on a page of your choice. The embed is more sophisticated than the competition, but again, it runs Java on the local machine, and your viewers will not necessarily want or be able to allow the installation. The applet takes time to load, which may put viewers off. Finally, ThinkFree's embedding process works slightly differently than the others. For one thing, you'll need to post a .ppt file somewhere on the open web. You'll need to go to the ThinkFree Viewer to generate the code snippet. Paradoxically, I found no way to embed a show that was stored in my ThinkFree account. Worst of all, though, I've had sporadic trouble viewing an embedded show through Firefox on a PC. Depending on which browser and platform you are using, you may be able to confirm this finding.