As a manager who has hired hundreds of developers I always ask for a portfolio, with links to live sites.
Right-click, view source!
Can reveal a lot about a developers habits and practices.
I also expect a GitHub repo. Fyi, personal sites and projects are just as important as the ones you get paid to build.
IMHO LinkedIn is a waste of time. People struggle to keep it up to date and most don't have the time to put enough detail into their profile that it says very little about the candidate.