Signals - See who opens your email

Their landing page is very well executed. Immediately I understand the product. Go to the site, you'll see what I mean.

Also, well-known (and super useful) ToutApp (http://toutapp.com) offers similar but even more functionality.

Awesome tool! Very well hunted @daveambrose!

They also have a pretty solid team-account onboarding UX.

Been using this since their beta release and a "must" in my email workflow. The "word of mouth" referral power is strong with this one...told a few friends that you can track email opens and clicks...BOOM, signed up!