A Link is what has opened this new Tiddler from within the last one; Links take the form of HighlightedWords, and anyone familiar with the internet will know what they are. A single click on the word opens the linked Tiddler ( think of it as a 'page' or 'note').

In general a Link denotes an immediate and specific association between material in one Tiddler and material in the other one, whereas Tags denote thematic connections under which a whole range of sub-topics may sit (think of Tags as chapter-headings, and Links as footnotes, if you like.)

You can check which other Tiddlers have Links to the one you are reading by clicking on the References section of the individual Tiddler menu (see the additional or related information section.)

More about links

There is a bit more detail on making links and cleverer ways of making links at Links and Shortcuts to making them