You can view a comprehensive info page per PodWiki page.
On this page you can see all revisions of a page. Beside viewing the revision you are interested by clicking on "view" link you can also click on the link diff to VERSION, which displays the differences between this and the previous version.
New content will be displayed in green color, removed content in orange color and unchanged content in grey color.
You can also click on the RESTORE button to make an older revision of a page current. This way you have the possibility to undo almost all changes made to a page.