Probably too long, if you've not given up already
HuliMail takes an email address (or a batch of email addresses) and shows you their LinkedIn, twitter and other profiles. It can even alert you the instant someone signs up if they look particularly interesting.
Scott Britton used HuliMail to find opportunities to connect in his existing email list
I'd highly recommend HuliMail to marketers, sales people, entrepreneurs, and anyone looking to maximize opportunities from their mailing list. I couldn't identify specific people from my mailing list who would be valuable for me to connect with. HuliMail allowed me to identify these people in a variety of contexts. I really like how I can filter my connections to find exactly the type of people I'm looking to connect with.
Gary Sieling used the HuliMail API to get a better understanding of people signing up for trial accounts of Osmosis
I'm using HuliMail to learn about my prospective customers - what industries they are in, and their role within an organization. Whenever a client sets up a trial account with our product, we get an email with information about the person (e.g. a description of the company they work for, their twitter, a photo or logo, as available). I've developed greater situational awareness of the state of our trial accounts. It's allowed me to identify people who renew trials after long absence, or after switching companies, or who have their colleagues set up accounts. This identifies people who might become product champions within their organization.