We use in it.source (and the idea has been exported into some other projects) a template, who builds a user defined, invisible anchor and "marks" some text near the anchor; the marked text will be highlighed (with a coloured background) only when the anchor is the target of a link (coming from everywhere: the same project, a wiki project, or an external link).
The template is [[:it:s:Template:§]], and it has been recently intoduced into en.source as [[:en:s:Template:Anchor2]].
Here an example pointing to Divina Commedia: http://it.wikisource.org/wiki/Divina_Commedia/Inferno/Canto_I#Ed_ecco
Consider that: # presently you'll see the highlighting with Firefox only; # the following additional row of code has to be added into your own common.css and vector.css, of should be added to Common.css by a sysop:
*span.Citazione:target {background-color:#DEF;}
*where "Citazione" is the name of the class used into the template:
<span id="{{{1}}}" title="Ancora:{{{1}}}" class="Citazione">{{ #ifeq:{{{2|}}} || |{{{2}}}</span> }}
It would be great if source project could add that row of css into their Common.css, allowing external users to see the highlighting feature where a template §, or similar ones, has been seeded.
Alex