Wikipack is a personal wiki. It is also a web application that "transparently syncs your data with Dropbox via their secure API." Using plain text files, it also allows you to format your documents with Markdown.
It allows for free links this "[[CoolStuff|cool stuff]]"
I have not tried it and probably will not try it, but it looks interesting and might be plausible for someone with needs that differ from mine.
No further comment!