I forgot to update this post, but Fun with core2 styles and CSS: filtering posts on your reading page has more tips on customizing on Dreamwidth. As I made a comment to linkspam, for Dreamwidth:

1) If your readers prefer to put all posts under cut, ask them go to Custom CSS and input in the Use embedded CSS: .page-read .entry-wrapper+.journal-newslettercommunity { display: none;}
AND/OR
2) If your readers prefer to put long posts under cut, use this as your posting template for long posts: <div class="newslettercommunity-content.long"> [body of newsletter] </div>. Then ask your reader to go to Custom CSS and input in the Use embedded CSS: .newslettercommunity-content.long { display: none !important; }