+ Free version
+ Easy to use
+ Great tool to start your marketing
- No build in lead scoring
- Response management
Mailchimp is often known for their email marketing functionality, however they do a lot more nowadays. You can actually start generating new leads with Mailchimp via their signups forms or landing pages. They recently launched also a lot of social features like; creating lookalike audiences, sponsored posts and lots more.
If you are starting out with marketing Mailchimp is a great tool. If you want to get more powerfull marketing we would recommend looking at the marketing automation tools.