Try adding a pubDate
-- publication date -- to your items. This is an optional item for RSS, so it's valid without, but Mailchimp requires it, I believe.
If you're coding the feed yourself in PHP, bear in mind that PHP's date formatting constants helpfully include DATE_RSS
/DateTime::RSS
.
Mailchimp also has an example RSS feed shown in one of their Support articles -- if you're still having problems, compare your feed to that example.
Also, note (from here):
When you first set up an RSS campaign
we will show the last post as an
example if you haven't added an
article in a few days. If this is your
first send, we'll only send the posts
from 24 hours before your campaign was
activated for daily, from the last 7
days for weekly, and the past 30 days
for monthly.
So I'm fairly sure that's why one of your posts is showing up -- because there's no publication date on any of them, Mailchip is just showing you the first one it finds as an example.