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I have found the best way track Facebook and Twitter is through Google Analytics. Google Analytics automatically tracks Google Plus on initial setup, but for Facebook and twitter it requires additional code within the share buttons. You can find the documentation to setting this up at Google Developers Social Interactions - Web Tracking. Let me know if you have any additional questions or need any help with implementation.

In css there are classes and id's. Classes have a period, so it would look something like this in your css file -

.nav { }

ID's have a # sign so it would look like this -

#homelink { }

You can also string these different elements together to target a specific element, but your question the code within your html file should look something like the code below. That id will trigger the css element have listed. Replace 'www.link-to-your-page.com' with your link.

Your Link Name