This is great, finally contact cards done right in Lync.
You can Link multiple sources together just like you can in Widows Phone 7 & 8

Then all the information is aggregated into one single contact card.
Information coming from various Sources : Active Directory, Outlook, Lync, Linkedin & Facebook
You can clearly where information is coming from when duplicate information exists.

I do have multiple Lync accounts so if you click next to the IM button you have a choice which account you want to contact

Finally you can even edit right from within the contact card.  This information will be saved in Outlook Contacts

How cool is that.
Even search in Lync 2013 works much better than in Lync 2010.
You can for example search for a company (did not work in Lync 2010)

Now we just need the social connector for Twitter & Skype and all is complete