WikiFormatting
One of the most common types of editing for RecentChanges patrollers is to help people understand the simplicity of WikiSyntax (basic wiki formatting) over html. (WYSIWYG or WizyWig is a way to have formatting changes like word or other major applications. What you see is what you get. )
Examples
If someone writes <b>Here is some bold text</b> and it gets changed to '''Here is some bold text'''.
When someone writes a list with out breaking the lines with a colon : then they all just run together on one line.
For both example: try to use as a HelpfulEditSummaries in the EditSummary: WikiFormatting.