I'm not sure how that would work, because the very nature of the beast is exceedingly personal. As I mentioned in the example I added to my original comment, it is about small things that, cumulatively, add up to big things.

I think the kinds of things that would show up on a rosettacode-type site are most likely already exposed in terms of plugins of some sort (however the editor defines "plugin"). It is the murky area between keyboard macros and plugins that the programmable editor makes its mark, and those things are highly individualized.

It would be fun to have something like seewhatididinmyeditor.com, that just let you post snippets of these kinds of things in your editor's native tongue.

Here's another example: I was converting some javascript to coffeescript. Coffeeescript's conventions are snake_case, and I wanted to follow those conventions, so I added this little thing:

  (defun my-uncamelize (s &optional sep start)
    "Convert CamelCase string S to lower case with word separator SEP.
      Default for SEP is an underscore \"_\".
      If third argument START is non-nil, convert words after that
      index in STRING."
    (let ((case-fold-search nil))
      (while (string-match "[A-Z]" s (or start 1))
        (setq s (replace-match (concat (or sep "_")
                                       (downcase (match-string 0 s)))
                               t nil s)))
      (downcase s)))

Now, I didn't write it; I grabbed it as a snippet somebody else had written and shared. Now, with a bound key, I had a single key-stroke that would snake-case an identifier.

Again, not a big deal, but it made the workflow for converting those js files just that much easier.