An autoresponder is an application triggered when a user sends an email to a specific address or submits a web-form.
Autoresponders can provide an automated email response to inquiries from potential customers, people who have signed up to receive your blog’s newsletters or if you’re offering a free course from your site. Such an email may newsletters with details on all the new content you’ve published on your blog, different parts of a free email course that you’ve set up or simply just saying thank you for signing up, with details on what to expect from your emails in the future.
More sophisticated autoresponders can be configured to send follow-up correspondence, keeping your blog “top-of-mind”.
It’s worth mentioning that setting up a professional email account would add more trust to your brand when sending out emails. The last thing you want is to be sending out emails via a free gmail account or hotmail.