Basically, a newsletter sends the same email to all subscribers at the same time. When you add an article to your site or send a broadcast "newsflash" campaign, that message will be sent to all the appropriate subscribers on the list. It's a typical email marketing update or blast, if you will. Furthermore, as long as you add articles and send mailings, a newsletter runs for ever. A subscriber will continue to receive mailings from the newsletter until they unsubscribe or their email bounces.
An autoresponder, on the other hand, sends a predetermined sequence of emails to subscribers, and the mail that's sent depends on when the subscriber joins the autoresponder's list. So different subscribers receive different messages on any given day. Further, once a subscriber has run through the autoresponder's sequence of messages, they don't get any more emails from the responder, even if they don't unsubscribe and their email is still good.
An example might make this clearer.
Say you are using a FeedBlitz newsletter to mail your subscribers every day, and you write a single message every day. Say the newsletter's article titles are "Monday's Memo", "Tuesday's Tips" etc., depending on the day of the week that you want them to go out.
During the week, Anne, Bob, and Charlie all subscribe to this newsletter. Anne subscribes Monday in time to receive "Monday's Memo", Bob subscribes Tuesday in time to receive "Tuesday's Tips" and Charlie subscribes Wednesday in time to receive "Wednesday's Wrap-Up".
So on Monday, Anne gets "Monday's Memo."
On Tuesday, both Anne and Bob get "Tuesday's Tips."
On Wednesday, Anne, Bob and Charlie all get "Wednesday's Wrap-Up"
Going forward, on the same day they all get the same email as long as you, the list publisher, keep adding content.
Now let's say that as an incentive to attract new subscribers, you offer a free three-part email "Timeless Tips to Triumph" course to new subscribers. Here's what you want to happen:
Subscriber subscribes: Send "Thank You and Timeless Tip #1"
A day later, send "Timeless Tip #2"
A day after that, send "Timeless Tip #3"
This is what an autoresponder does. In FeedBlitz, you create the autoresponder and link it to the "parent" newsletter. When a new subscriber subscribes to the parent list, the autoresponder starts.
So on Monday, Anne gets "Timeless Tip #1"
On Tuesday, Anne gets "Timeless Tip #2" and Bob gets "Timeless Tip #1"
On Wednesday, Anne gets "Timeless Tip #3" and Bob gets "Timeless Tip #2" and Charlie gets "Timeless Tip #1"
On Thursday, Anne gets nothing from the autoresponder (she's finished it), Bob gets "Timeless Tip #3" and Charlie gets "Timeless Tip #2"
On Friday, Anne gets nothing, Bob gets nothing, and Charlie gets "Timeless Tip #3"
From Saturday on, no messages are sent from the autoresponder to Anne, Bob or Charlie because they're all finished BUT the newsletter keeps on mailing them.
So the autoresponder sends a fixed sequence of emails (timeless tips 1, 2 and 3) on a fixed schedule (immediately, a day later, a day after that). And each subscriber gets a different email on any given day, depending on when they join the list.