iframes, which is nice if you're not big on design. (But please serve pure HTML as well for people to style themselves.)
The benefit for careers is obvious: You tie your users to your service even more closely; users have even more reason to keep their data up to date; the embeds drive potential employers to the site.
Possible features (feel free to edit and/or make CW):
A careers flair showing top x% positions. Something like this:
Maybe show a careers logo on that one - bragging is so much easier when it's a third party providing the facts. :)
A careers flair showing key data
A styled JS embed for the "experience" table, like so:
A styled JS embed for the "education" table
- Full profile
- Pretty much every other section, in nice semantic HTML of course.