LinkedIn for Salesforce
To integrate LI and SFDC follow the procedure found here
Forget groups and other features of LinkedIn. By far the most powerful feature of LinkedIn is keeping track of your contacts when they move. Tracking 'cold' movers is great too, but let's be frank: tracking your own connections when they move is the A game.
So, every contact that you've ever met and recorded in Salesforce should be a connection, and every prospect should be researched on LinkedIn before you contact them. But that means toggling between Salesforce and LinkedIn, right?
The LinkedIn for Salesforce app on the Appexchange is a great way to integrate the two right into your CRM. If you already have a premium account with LinkedIn, then this app will cost you nothing. And if you don't have a premium account, you probably should consider upgrading anyway as a premium account allows you to create filters and alerts to track cold movers and find new prospects.
Once you install LinkedIn for Salesforce there is quite a bit of fiddling to get it fully integrated, but it's worth while. Open a contact and you will see the full LinkedIn profile right within your CRM, including who else you are connected with and their history. Take a look at their company (still in the contacts) and you'll get the company profile including who else in that company you might want to know or to research.
To add more LinkedIn contacts, or to keep your current ones up to date, create a view in Contacts to show all contacts that you don't yet connect with and visit this once a month or more to add all your new contacts as connections. If you've just added a new contact it's likely that you have recently met them, so what better time to connect with them on LinkedIn also?