When I first started my little ecommerce business, I used an @yahoo email account. It worked fine. I didn’t have a lot of orders and I wasn’t really worried about security. Six months after my business really took off, my free account was hacked and every single customer I had ever emailed received a spam message, seemingly from me. That’s when I realized I needed an email service provider. Now I’m sure that the only emails my customers get from me are the emails I want them to receive.