Page titles (the text that appears in your browser’s top window bar) are a very important element in how search engines determine your site’s evaluation / ranking.
It is highly recommended that your page titles include keywords used in the content of the specific page.
WordPress users, using some of the themes available on the web, can find that WordPress 2.0, combined with the theme they are using, will stop showing post names in the page titles.
In order to fix this problem you will have to manually edit your theme’s template.
Another option is to choose the default theme provided with WordPress, which shows the post name in the title, and start building your own theme based upon it.