The apply with linkedin button allows you to apply for jobs on LinkedIn.
http://developer.linkedin.com/plugins/apply
Widgets
Get access to data on 1,353 websites that are Linkedin Apply Button Customers. We know of 238 live websites using Linkedin Apply Button and an additional 1,115 sites that used Linkedin Apply Button historically and 66 websites in the United States.
Get a list of 1,353 websites using Linkedin Apply Button which includes location information, hosting data, contact details, 238 currently live websites and an additional 46 domains that redirect to sites in this list. 1,115 sites that used this technology previously and 66 websites in the United States currently using Linkedin Apply Button.