Im worried about scalability. What happens if Wikibooks is invaded by hordes of new people who don understand whats going on here, and mess it up?
Wikibooks has a large number of dedicated volunteers who welcome newcomers, edit their contributions and point them to appropriate help pages to get them started. Our software maintains a complete history of page revisions, so Wikibookians can quickly undo any accidental (and intentional!) damage. Wikipedia, for example, has been Slashdotted twice, and yet handled the influx of newcomers with no problems.