Rapportive is a free app (recently acquired by LinkedIn) that shows you everything about your contacts right inside your inbox. Rapportive helps you build rapport quickly (hence the name) and is "relationship management built into your…

WiseStamp is a handy dandy app that allows you to customize your email signature.

I use the free version in conjunction with Gmail and it works swimmingly well for both branding and presenting a professional signature from a web-based email account. WiseStamp is compatible with other…