This I did not know about. In the far away history of my teaching career I did once train the original SharePoint class. I did not like it. And if it wasn't for workflow, I would not have touched it since. But when a colleague showed this new-hire a Slide Library, I had to admit I like it! For someone who creates a lot of presentations, collaborating on those presentations is hard. Unlike source code, merge is not really an option, but SharePoint 2007's slide libraries is the next best thing: each user can edit an individual slide (locked for editing) and once everyone contributed their slides, SharePoint will give you one big PowerPoint file with all the slides combined into one presentation. Of all the operational details I learned in my first two weeks at Microsoft, this was the best!