You know how almost every GUI-based OS allows you some equivalent of a "clipboard" with ctrl-x ctrl-v or similar? Let's take that one level further, and make *everything* on your computer work as a *user configurable* hyperlink (and hyperlink target as well).
This should be part of every
OS just as the "clipboard" metaphor is today.
Hyperlinks should be more than just stuff you click while in a web browser, and they should be more than just 'author definable'.
Some have made scripts that allow you to click on a word in a web page for an automatic dictionary lookup. What I'm talking about is more flexible than that.
Any time you click on anything clickable in any application, you should be able to press (some unique button or key-combo) to treat that thing as a hyperlink to something else (another doc, a program, a webservice, whatever you want).
The user gets a "registry" where she can define all default actions.
Default actions are subsets of filetypes, so clicking on a word in a *.txt file can result in a different action than clicking on a word in a *.js file, or a *.csv file, or whatever.
Also, scrolling the mouse wheel should allow the user to change the default action, so that clicking on a word in a *.foo file can do more than just one thing all the time: (e.g., 1:find in dictionary, 2:find in address book, 3:navigate as weblink).
To make this system simple, the user can define "global default" actions for *.* ... where the settings apply to all filetypes.
You can also define universal targets (eg UHX://c:/docs/MyAddressBook.txt#Lisa)
takes you to the first occurance of the word "Lisa" in your file, regardless of filetype or whether it is an HTML doc with an ANAME tag.
Note, since *everything* is a hyperlink, you could also click on ( MyAddressBook::Lisa ) and have the UHX handler translate it into the previous link. The flexibility renders your entire computer into a "mini web" of sorts.
BENEFIT: The main benefit of this idea, is that the user can now work with individual *elements* within a file just as flexibly as she can with *entire* files.
PITFALLS: Initially, this will only work with text files.
NOTE: This is not XLINK. This is not Wiki. This is a ubiquitous tool that is just like a 'clipboard' for your OS.