Edit summaries, entered below the edit box, next to "Summary:", are helpful for other editors to understand your edits. In some cases, particularly moving content between pages (e.g. splitting a page) a clear edit summary is essential.
Moving or copying content[edit source]
If moving content between Appropedia pages, this must be explained in the edit summary on both the page of origin and the target. This is how Attribution is given in these cases. Attribution to an editor is recorded in the history page for any article - however, if moving part of a page but cut-and-paste, the actual creator of the content is only recorded on the original article's history page. Therefore, the source must be mentioned on the target page (where the content is posted).
On the source page (where the content was cut from) the edit summary is important to explain to other editors why you are removing good content from the page. If there is no edit summary, other editors are more likely to revert your changes.
When copying content (not deleting it from the source), then an edit summary is needed on the target page, saying where it's from.
The edit summary should give the exact pagename of relevance. Use double square brackets (to avoid confusion and to create a link in RecentChanges and in the history page entry. E.g. "Added content from [[Foo]]." Or "Moved section to [[Foo2]]<
(On the subject of attribution: If the source page has an attribution notice on it, this notice should be copied and used on the target page as well. Only leave the notice out if you're completely certain that the particular section you're moving is not from that source.)