Daily fetches an RSS feed and posts a list of links as a digest post to your blog. (Note that this is in pre-ALPHA development).
That's what I am wondering too ;) No, seriously, this is high up on the list of things that this plugin needs.
If you want to help making this plugin more useful, feel free to drop me a line
at fwenzel at mozilla dot com. If you are "PHP-savvy", you may also change some
of the code you find in the SVN repository
http://svn.wp-plugins.org/digest-post/trunk/) and send me a patch. I very
much appreciate it!
No, the plugin stores the time stamp it last posted a digest, and the next time it runs, it will only include items in the digest that have a time stamp after the last post.
No, not at the moment. But if you'd like to add this feature, you are very welcome to help me out! (See the section on how you can help above.)