Constant Contact and Mailchimp are two common services that can help you manage your email marketing campaigns. Both allow you to manage different mailing lists, run campaigns, and look at quantifiable metrics relative to whether people opened your emails and/or clicked the links inside the emails. They are also great at automating list generations from email signups on web sites and mobile apps.
All-in-one marketing platforms like Hubspot and ThriveHive allow you to manage your entire online footprint in one place.
Best-in-class testing platforms like Optimizely and Unbounce.com allow you to run A-B tests and track every activity in your funnel from an email blast onward.