The changed page can include an HTML META to force a refresh for everyone.
@ Acorn: Agree Acorn but how many Xara users know how & why to do this?

@ Miko:
When I visit a regular site I get an updated version.
No you don't necessarily, you would normally load a cached version of the site from your local computer from your previous visit. So unless you change the meta info as Acorn suggests the old site will be rendered.