You could hide some contents in posts, then those who have not replied to any posts will not see them.
Manage footer code snippets from within WordPress. No need to edit your theme's footer.php file any more.
Creates a little quote icon in comment boxes which, when clicked, copies that comment to the comment box wrapped in blockquotes.
This widget displays the saint of the day, according to the timetable of the ordinary and/or the extraordinary form of Roman Catholic rite.
Flash Feed Scroll Reader is a Adobe Flash Feed Reader with horizontal scrolling.
Retrieve pages, and children, in a more sophisticated way and add the correct class to the parent li-element even if you're visting a child-page.
Displays all of your online identities (Twitter, Facebook, Flickr, LinkedIn, YouTube, more) as clickable links in your sidebar.
ajaxcoderender is a plugin to make your code in post looks pretty
The Menu Maker plugin helps in creating a menu for your site. Usually this can be used for creating a navigation menu.
Define custom styles for any post, page, or custom post type. Example: journal-style publications which want to create a unique design for articles.
This plugin will allow you to check your entire site against the W3C Validator.
WordPress Filter is a comprehensive post filtering & template system. It allows the user to define a set of simple "Catches" (criteria) to be met
WP-SmugMug integrates your SmugMug galleries into your Posts and Pages on your WordPress blog.
Article2pdf let your visitors download a post as PDF file: images, formats, lists, tables included. You can use a PDF as template file and much more.