This is a really cool hack but I would never hand over my email creds to someone like LinkedIn after their history with emails. They might decide one day to "help" you by inviting everyone you have emailed or has emailed you or they could start added a "Connect With Josh" link to the bottom of my outgoing emails that links to my LinkedIn.

Again, VERY cool how they did it but it requires quite a bit trust in a company that I don't find very trustworthy.