TinyEmail is a tool I've discovered only recently for a side project. We usually send newsletter and outreach emails using Mailchimp, but for a completely separate project we've decided to try out TinyEmail as a lightweight mailchimp alternative and... it worked.
TinyEmail does almost everything mailchimp can, but because it's actually lighter on the functionality it's a bit faster and easier to work with. Composing emails is fast, lists managing is simple and analytics is very useful. So i'd say its a worthy addition/replacement to mailchimp.
Keep in mind that TinyEmail is a simplified version of Mailchimp, so don't expect things like advanced html template builder or pop-up subscription forms. I'm more than agree with such limitations (as that's the point of the service), but go into it expecting this.
A very simple and straight-forward mass email and automation solution. Very clean and easy-to-use.
Sending quick and personalized emails to follow up or reconnect with leads or potential partners.