An edit summary is a brief note you leave in the small text box below the main editing box, to explain what you have done to the article. This will appear in "recent changes" and people's watchlists, and also above any "difference" view of the article. It is good form to try to make them clear and concise, so other editors will be able to decide whether or not they want to check out the change.
Rationalwiki is somewhat cavalier about edit summaries and while you may not be castigated for not using them, it's still considered polite to.
 Edit summary
Always fill in the summary field. This is considered an important guideline. Even a short summary is better than no summary. An edit summary is even more important if you delete any text; otherwise, people may question your motives for the edit. Also, mentioning one change but not another one can be misleading to someone who finds the other one more important; add "and misc." to cover the other change(s).
Accurate summaries help people decide whether it is worthwhile for them to check a change. We've found that summaries often pique the interest of contributors with expertise in the area. This may not be as necessary for "minor changes", but "fixed spelling" would be nice even then.
In the case of a small addition to an article, it is highly recommended to copy the full text of this addition to the summary field, giving a maximum of information with a minimum of effort. Put ft in front, as an abbreviation of "full text" (see the Abbreviations section for other abbreviations). This way, readers of the summary will be unlikely to check the page itself as they already know the extent of the edit. It also makes it easy for color-blind or visually impaired readers to see punctuation and other tiny changes that may be difficult to discern. It also helps users to check Recent changes, Page history and User contributions very efficiently, and reduces the load on the servers.
If the addition is more than 200 characters, so it does not fit fully in the edit summary box, you should write a short summary of the changes you have introduced into the article. For an addition of, say, 400 characters you can also save time by simply copying that into the summary field. The excess will fall off, and the first 200 characters will usually be acceptable as a crude "summary".
Unfortunately you can copy only one line of text from the edit box into the edit summary box. The contents of further lines can be pasted at the end of the line. Thus, for example, a bulleted "see also" list is cumbersome to put in the edit summary box. One possible workaround for a new list is putting the list on one line, separated by the asterisks for the bullets, copying it to the edit summary box, and then, in the main edit box, putting the new lines before the asterisks.
In addition to a summary of the change itself, the summary field may also contain an explanation of the change; note that if the reason for an edit is not clear, it is more likely to be reverted, especially in the case that some text is deleted. To give a longer explanation, use the Talk page and put in the edit summary "see Talk".
After saving the page, the summary cannot be edited--another reason to avoid spelling errors.
In the case of important omissions or errors in the edit summary, you can make a dummy edit just to put the correction in the edit summary.
This is a list of commonly used edit summary abbreviations. This page does not lay down any official guidelines on how to fill out an article's edit summary. RationalWikians are encouraged to write accurate and detailed summaries.
 Addition of category
- cat, +cat
- [[Category:Whatever]] will put a link to the appropriate category page into the edit summary
 Addition of comment
- cm or re followed by either the comment itself or the topic.
- Meaning: I added a comment to this page
- cm rattlesnake
- re : rattlesnake
- EL, xl, ext lk, ext lks, ext lnk, ext lnks, ext link, ext links, URL, http
- Meaning: I have added an external link to the article.
- If there is possibility for confusion, name the link specifically.
- Example: ext lk: Richard Dawkins.net
- lk, lks, link, links, ln, wikilink, wl.
- Meaning: I have created a link from this RationalWiki article to another one.
- In the summary, put the link between single apostrophes ('), or copy it from the edit box so that it appears in double brackets[[ ]]
- This is especially useful when the link is to a new article: people watchlisting the current page are likely to be interested in the new page.
- link: 'Train'
- lks: 'snow', 'hail'
- See also: Addition of external links.
 Addition or rephrasing of a short text
- ft followed by the full text that has been added (perhaps with a little context), or the new version of what was changed.
- Thus the edit summary fully informs about the edit; there is no need to open the article unless you want to see the text in context
 Addition of text
- +, add, addition
- Meaning: I have added text to the article, and here's a summary.
- +Future expeditions or add:Future Expeditions"
- alpha, abc
- Meaning: I have put this list in alphabetical order.
- cap, caps, capital, cpt, lc, lcase, uc, ucase
- Wiki article titles are case-sensitive, except for the first letter of the article, which always appears as a capital. Also, according to Wiki style, only the first letter of the first word in section headings should be capitalized. The above abbreviations indicate fixing of capitalization mistakes, or lowercasing or uppercasing specific words. cap, capital, cpt indicate general fixing of capitalization. caps is for those instances when every letter of a word is capitalized, when the word is to be made ALL CAPS. lc and lcase mean lowercasing the first letter of some word, and uc and ucase mean uppercasing the first letter of some word.
- cl, cleanup
- Meaning: "I have made some general "tidying-up edits." These may include reformatting, spelling and grammar fixes, markup fixes, and other such minor edits. Useful if you make many different kinds of small changes in a single edit.
 Copy edit
- copyedit, cpyed, ced, c/e
- It is encouraged that you specify the changes.
- copyedit: major reorganization, left original text
- cpyed: from 'Tell Joe and I to ...' to 'Tell Joe and me to ...'
- 'It took 4 years to build...' -> 'It took four years to build...'
 Creation of a new article
- creation, new
- Meaning: I have created a new article.
- If there are remarks you wish to make, add them after two single dashes (-).
- No other abbreviations need to be used since the article is new.
- creation -- POV check please
- new -- POV check please
- dab, disambig
- See horizontal rule
 Edit that is explained on the article's Talk Page
- see Talk, see talk
- Meaning: I have discussed / explained this edit on the article's talk page.
- If possible, combine with other text, e.g rephrased, see Talk.
- fm, fmt, frmt, formatting
- Meaning: "I have applied formatting to this article". For example, to adhere to RationalWiki's general style, or to make the look consistent, etc.
- There is no need to specify the formatted text.
- gm, gr, grmr
- Meaning: I have fixed the grammar of a sentence.
- head, h2, h3, h4, h5, h6
- Meaning: I have fixed header markup or changed header wording. Often seen when a page has been incorrectly laid out with level 3 headers at the top level (=== text ===) instead of level 2 headers (== text ==).
 Horizontal rule
- Meaning: I have added (or removed) a horizontal rule (----).
- mrg, mrgd, merged in
- Meaning: I have merged some other article(s) into this article.
- All the articles merged should be specified.
- Example (for United States of America): mrgd: USA & United States of America
- Miscellaneous edits
- Use only when a more specific and more useful edit summary is not practical.
- Meaning: I have moved the article or part of it to another location. (The new location should be specified.)
- Or: I have added some material which comes from another article.
(Where it comes from should be specified)
- mv to 'United States' (mrgd)
- mv from 'America'
 Null edit
- null, nx, ø
- The edit window has been opened and the page re-saved with no change of text (occasionally necessitated by non-automated changes, like those to templates included in the page).
- punc, punct
- Meaning: I have made edits to rectify punctuation. (Elaborate as needed).
- re-cat, recat
- Meaning: I have made changes to a pre-existing category link or links.
- If the change is specified, put the category link(s) between single apostrophes (') or double brackets (e.g., [[Category:Category name]]).
- recat 'Old category' to 'New category'
- recat [[Category:Old category]] to [[Category:New category]]
- REDIRECT 'Article Name', rd 'Article name', redir 'Article name'
- Meaning: I have made the page redirect to another place.
- The page that the article redirects to should be specified.
 Removal of text
- -, rm, remove, del
- Meaning: I have removed some text from the article.
- -some crazy folk
- remove: some crazy folk
 Revert to a previous edit
- revert, rv, r
- Reverted to a previous edit.
- This short summary is insufficient on its own — you should always briefly explain the reason for reverting.
- rv: accident
- rv: vandalism
- revert blanking
- rv unexpl del — revert unexplained deletion
- rv changes by User:Second user to last version by User:First user
- rvv or rv/v = revert vandalism
- rvs or rv/s = revert spam
 Snap double redirect
- snap dbl rdr, fix redir
- Turned a double redirect into a single redirect
- sp, spelling, typo
- Meaning: I have fixed some spelling mistakes.
- It is not usually necessary to specify the spelling change but if you must, format it like this:
- desparate -> desperate
- sp, typo, typos, tpyo, tpyos, tyop, tyops
- Fixed typos.
- There is no need to specify the corrected typos.
- (A "typo" is a typographical error: a keying mistake for example.)
 User experienced edit conflict
- wikified, wikify, wfy, wky, wkfy, wiki, wk
- Meaning: I have created Wiki links or converted Wiki markups
- This is used especially in the case of new articles.
- There is no need to specify the wikified words.
 Dummy edit
A dummy edit is a change in wikitext that has little or no effect on the rendered page, but saves a useful dummy edit summary. The dummy edit summary can be used for text messaging, and correcting a previous edit summary such as an accidental marking of a previous edit as "minor". Text messaging via the edit summary is a way of communicating with other editors. Text messages may be seen by dotted IP number editors who don't have a user talk page, or editors who haven't read the subject's talk page, if it exists. Each edit summary can hold 200 text characters. A dummy edit should be checkboxed "minor" by logged-in editors.
- Changing the number of newlines in the edit text. Changing from 0 to 1 or from 2 to 3 (or vice versa) has no effect on the rendered page. Changing from 1 to 2 newlines makes a rendered difference that may not be a dummy edit. Adding newlines to the end of the article will not save as a dummy edit (see below).
- Changing the number of spaces. Changing one space character to two or more (or vice versa) also has no effect on the rendered page. Multiple space characters always render as a single space, unless the line begins with a leading space.
 See Also
The above has been copied (and subsequently modified) from Wikipedia's "Help" pages.