High Quality Content by WIKIPEDIA articles! CareerBuilder.com, operated by CareerBuilder, is the largest online employment website in the United States, with more than 24 million unique visitors each month and a 34% market share of help-wanted web sites in the United States. CareerBuilder.com provides online career search services for more than 1,900 partners as of March 2008, including 140 newspapers and portals such as AOL and MSN.