This would not affect things in most cases because most WikiWord(s) would be written apart (like "wiki words") if they were not consciously meant to be a link.
But it would make free links easier when a wiki had a relatively high percentage of content about subjects which do not easily fit into the LinkPattern. For example, on NeuroWiki there are wiki pages called "thalamus" and "2-AG", which i generally link to whenever I mention those words (using [[ ]], now that NeuroWiki has moved to UseMod). So as a slight convenience, it would be cool if NeuroWiki automatically made those things into links if the user forgot or didn't bother to make them FreeLinks on purpose.
It would be impractical to expect the WikiEngine to do this at the time of page display. The easiest way would probably to suggest the new FreeLinks to the author at the time of previewing an edited page. So the resulting functionality of this would actually be a restricted form of LinkSuggester?.
This idea would not be very earth-shattering; at the best it would be a small timesaver.
ProWiki also implements this. But still there is a "word link pattern" so that not every word need to be checked. The pattern is configurable. I don't think that a common word list is worth the effort, because you have to build a hash of "non-linking words" anyway to avoid rechecking for pages. Any matching word must unconditionally be checked against this hash. In English it might make sense to restrict automatic word linking to words of length>=5. It might be also interesting that ProWiki has a simple mechanism for "word form reduction", so it is able to optionally reduce "wikis" (- "s") to "wiki" or "linking" (- "ing") to "link", which is almost useless in German because of its more complex word forms. I used this extensively in what I call "the Ogden experiment", a kind of wiki-based semantical language analysis I did a while ago (any word in this 1000+ page wiki links). -- HelmutLeitner
GeboGebo supports AutoLink, too. It parses the page on display time and checks each word against the (indexed) database. A bit of confusion stays when using NameSpace s; should a matching page name be looked for in all namespaces, only the current or at least the current and the root NameSpace? All auto-generated links appear in a different color as the hand-made do.
Consider to AvoidClutterLinks.