This simple trick allows you to disable the WordPress admin bar completely for everyone and remove the preferences.

Disallow search engines from indexing posts in a certain category.

Using query_posts() is a very cool way to display, for example, latest posts of a specific category

The last thing you want is clients clicking the update/upgrade notice that appears at the top of the admin screen. What is out of sight is out of mind so here is one way of hiding it.

There are many Twitter plugins for WordPress but why not create your own ways of displaying your tweets with these 2 simple methods.