Yes. Next to the name of each page towards the top of each page there is an Edit and an Info button. Clicking the Info button displays the entire history of changes made to that page. This allows you to see what a previous change looked like and compare it to another change. The date, time, and user who made the change is also recorded. If the user did not log in when making the change, their IP address is recorded. Also, underneath the CU WIKI name at the top of every page are buttons to main parts of the site, including the Recent Changes button. Clicking the Recent Changes button displays a list of all the changes made to the site over the past seven days.
Yes. The paperclip button in the edit tool bar (the red rectangle below) allows you to upload a file to the page you're editing.
You can then make a link to the uploaded file so that others can see and download it. For a good example of a page with an uploaded file, see Difference Makers 2010. The file eBlackCU_Difference_Makers_2010.pdf has been uploaded to the page and a link to it has been added. If no link to the uploaded document is made, a visitor of that page probably won't know the document exists.