Microsoft have announced that is has acquired a minority stake of 4% in job-listings partner CareerBuilder.com and will use that job-search engine on MSN sites overseas in a bid to capture more of the classified advertising money migrating to the Web.

Microsoft has also agreed to extend a pre-existing partnership with CareerBuilder until 2013. The deal, in which Microsoft’s MSN network directs traffic to the recruitment site, could be worth $443m. It should also help CareerBuilder to speed the development of its international business.