Use Rapportive or these other great tools to engage with other individuals and potential partners:

• Google your Contact: See if you can pull up a personal blog or website. This is the best place to start. Understanding a potential partner's history and what topics shape his/her thought process are important.
• Visit their LinkedIn: Go to LinkedIn People Search to find your target contact. The individual might have their email publicly available along with their resume, however the most important thing about the linke din profile is understanding your potential partners history. Look for Academic Institutions, employment history, extra curricular and more...

• Use this Google Hack for finding their online profiles.
  
• Find an email: There are many ways to find someones email. If they have it publicly available ten you'll have little problem getting in contact with them. If you need to get more creative here are two great methods for finding someone's email.

Find the domain of the company your target contact operates from. Use Google to search for the contacts name + the company domain, a search would look like this: "firstname lastname + example.com"

or

2. Go to Gravatar Checker and use a similar method of entering the target's company domain substituting variations of the prefix. ex -
"k.johnson@manpacks.com", "ken.johnson@mapnpacks.com, "kenjohnson@manpacks.com" etc... If they have a registered gravatar, you'll know when you've hit their email when their face pops up.