Unfortunately, LinkedIn is much more restrictive, and not only it doesn’t send me notifications of birthdays (or shows me the list of following birthdays), but also isn’t allowing exporting to an application like Google Calendar.
Here’s where LinkedIn Birthday Reminders comes along. The application, in a few simple steps, allows you to download the data in a format which can then be later imported into Google Calendar. I find it very effective.
The use? Telling people “Happy birthday” is a great way to stay in touch. Also, some people don’t display their birthday on Facebook, but do so on LinkedIn, and you’ll have an advantage if you use this.