I've wanted for some time to make diffs more understandable to nonprogrammers. One of the clearest, most intuitive displays I've seen is cvsweb. It will give you color-coded, side-by-side comparisons of two versions of a page. (It's interesting to see a screenshot of Xanadu in this respect, because the two have similarities, but I digress).
Since you are using diff to do the comparisons, diff -y would give you side by side comparisons, and the regexps to turn this into color coded comparisons shouldn't be hard. Since the number of people in this world who understand ed commands (which diff's output is/can be compliant with) probably numbers only in the thousands, if not the hundreds, things like Changed: 1c1,9 serve only to confuse the user.
Another possibility is diff | ediff if you have ediff in stalled (it's billed as a "diff to English translator," and I found it in O'Reilly's Unix Power Tools.
Also consider [GNU wdiff]. This is a word-based (as opposed to line-based) diff frontend. Thus it can be used in either a Wiki:QuickDiff or Why:GoldBar display to highlight only the changed portion of a large paragraph. The [wdiff manual] has some cute examples of parsing the output.
I definately like the Why:GoldBar idea and the side-by-side diffs! I'm a programmer and I know diff quite well, but I still feel this is a much better solution for WIKI. Any chance it will be included in the next release? -- EvanLanglois (aka MeatBall:EvanLanglois).
Over at the UnrealWiki, we have replaced UseMod's built-in diff output by a Perl-driven word-by-word diff and a WikiPedia-style format of displaying the old and the new page version side by side. Some details about the display are user-configurable on the prefs page (color background or strike through/underline markup of deleted/added text, and display of paragraph marks à la Microsoft Word and other word processors). If there's interest, I'll see that I make it available on WikiPatches. --MichaelBuschbeck
As Netscape 4.x has serious issues with CSS (MeatBall:NetscapeMustDie), it's advisable for Netscape 4.x users to enable the "Use underline/strike through formatting for added/deleted text" option on the Preferences page. --MichaelBuschbeck