Rapportive is a free-plugin for Firefix, Safari, Mailplane or Chrome which shows you information about a contact — their job, company and LinkedIn profile, their latest tweets, links to their Facebook and Skype accounts and more. By logging into Rapportive, you can also leave notes for later right on their profile. Now you can see how else you can connect with a person in order to grow the relationship.
Social Information
When you open an email, Rapportive will try to look up a person’s various social profiles based on their email address. If you’re logged in, you’ll also see any notes you’ve left about the person.

Raplets
Rapportive also supports information from several different applications, allowing you to see even more information about a person. Currently supported applications are MailChimp, Bantam Live, BatchBook, BookingBug, Brightpearl and CrunchBase.
Minor Issues (fixed)
I have a business account with Google for my gmail and I haven’t been able to login to Rapportive from that account. I still am able to see pretty good information about contacts, such as their social network profiles, but I can’t leave any notes or tie into any Raplets. It looks like there are some instructions that may help resolve this issue, but I haven’t had a chance to try them yet.
UPDATE: I sent an email to Rapportive’s support and they were able to quickly help me get Rapportive working with my business domain gmail. It turns out that Google’s directions in this case were just about useless, but Rapportive was able to send me easy-to-follow directions which immediately fixed the problem.
What do you think? Have you tried Rapportive?