Why is using an email vendor important for email marketing?

I don't know any case studies, but a serious vendor is on the whitelist of the major mail-providers and interested to stay there, therefore runs a tight policy,

Using your own smtp server it is not easy to proof if the newsletters are ending in the spam-folders of several mail providers or reach the inbox.

e.g. www.mailchimp.com gives you a free contingent for testing, and others do it similar.

you could open email-accounts with many different mail providers and send out a newsletter to this control-group from your own smtp server, if you've got time enough for testing.

By vendor I assume that you mean an autoresponder service such as aweber, getresponse etc.

The reason to use this third party serive is that they take care of all the can-spam side of things and make sure that your list actually verify their email by a double opt-in process.

By doing this they keep their mail servers off the black lists and allow you to schedule the mailings to go at various intervals from someone joining your list, and also set up broadcasts for when you want to send traffic to an offer / new content.

They also provide all the html so you just cut & paste a line of code onto your website to make the opt-in box appear. Overall much more simple to use and reliable than trying to host the service yourself.

Andrew

http://www.listbuildingexpert.com/

There are a lot of bad vendors out there and several good vendors. A good vendor tracks individual delivery failures. A bad vendor has low-life customers selling viagra and other junk.

Vertical Response is one of many good vendors.