Global, better URL to citation conversion functionality
Suppose, in Wikipedia, all that needed to be done to generate a perfect citation was to provide a URL? That would be a tremendous step toward getting a much higher percentage of text in Wikipedia articles to be supported by inline citations.
There are already expanders (for the English Wikipedia, at least) that will convert an ISBN, DOI, or PMID, supplied by an editor, into a full, correct citation (footnote). These are in the process of being incorporated into the reference dialog of the VisualEditor extension, making it almost trivial (two clicks, paste, two clicks) to insert a reference.
For web pages, however, the existing functionality seems to be limited to a Firefox add-on. Its limits, besides the obvious requirement to use that browser (and to install the add-on), include an inability to extract the author and date from even the most standard pages (e.g., New York Times), and the lack of integration with MediaWiki.
For a similar approach, using a different plug-in/program, see this Wikipedia page about Zotero.
A full URL-to-citation engine would use the existing Cite4Wiki (Firefox add-on) code, perhaps, plus (unless these exist elsewhere) source-specific parameter specifications. For example, the NYT uses "<meta name="author" content="NICK BILTON" />" for its author information; that format would be known by the engine (via a specifications database). Each Wikipedia community would be responsible for coding these (except for a small starter set, as examples), in the way that communities are responsible for TemplateData for the new VisualEditor extension.
(Project idea suggested by John Broughton.)