Hi Lander,
I'm pleasured to meet this site.
Thank you for the contribution to Joomla! world and for your thoughtful articles, interesting, smart and concise.
Wish you all the best in education, career and spiritual self-realization!
About the glossary plugin usage:
I want to glossarize my site, which has tens of articles and tens of terms' instances in each article.
Embracketing them manually would be a crazy job.
So I could think of
(1) a function like in DokuWiki: some abbreviations in text are detected automatically by the engine, and so get a tooltip.
That would be the easiest way for the end-user: you don't write any brackets manually, you don't care to convert the text of a new article etc.
All you would do is to make a rule of matching for each term, like
glossar*
for all the forms of the "glossary" term, where * means any symbols till the end of the word.
So all the forms like "glossary, glossaries, glossaric, glossarize" etc get that tooltip.
It's especially important for synthetic languages like Russian.
(2) Another way would be to automatically change articles' text with such substitutions:
glossar* -->
glossar*
by running some tool from the backend. E.g. you set a list of rules, then run a mass search and get a table of articles with checkboxes. You uncheck those articles which you don't want to be tooltipped and press 'OK'...
(Maybe there is already some mass substitution tool for Joomla!, I'll look for it).
Another suggestion:
is it important to keep tooltips "pure CSS"?
A link to the full glossary entry (- etc, like links in Wikipedia's tooltips -) could be useful.
And if JS is disabled, they could gracefully downgrade to pure CSS...
PS. The tooltip shows a term name, then "Definition:", then the text of the definition.
Please remove "Definition:" line from the tooltip, it's kinda obviious.
Besides, it takes space and doesn't correspond to some languages.

Cheers!