If you have installed some plugin that adds shortcodes like [shortcode id=1] (for example [nggallery id=4], [tweeetmeme id=4 section=Name] etc), one you remove that, this pieces of text will appear in your post content unprocessed (just appear like they are in backend). WordPress has it’s own Shortcode API, so managing them is very easy. So if you don’t plan to use it or just temporary disable, you can use a pretty simple function that you can add to any plugin or theme’s functions.php that removes any shortcode you want from post output:
Some professional WordPress websites usually have custom post roll layout and different post count on homepage. So this means when you go to second page of post roll you should’t see repeating items as a consequence of another post count than set in ‘Blog pages show at most’ setting in Reading section of Settings in WP-admin.
Since version 3.0, regular WordPress and WordPress MU are merged into WordPress 3. All betas of WP 3.0 had Site Admin section in backend (even if upgraded from regular WordPress), but since RC and final release this option disappeared. It is a hidden part of WordPress 3.0 and has to be activated manually with a a few edits to a WordPress installations wp-config.php file. You need FTP or shell access to do it.