The html <title> tag is shown by browser in the bar at the very top and usually as the tab title if you browser use tabs. Is search engine it is displayed as the first line of each results, big bold and linked to the page (see example with yahoo!)

Important for both the users and the search engine, it is important to have clear and unique title tag on each page.

For example instead of starting the title by the blog name and then the post name do it the other way round. So when someone use a search engine and browse a page where your article is, he will see first what’s important to him: the subject.

In the default wordpress template this is not the case. If you open header.php you will see a line like this:

Which means in English: Blog Title then, if we are showing a category, the word ‘archive’, then the title of the page/post.

A simple improvement is to swap blog_title()  and wp_title() to get something like:

You can of course complicate the display with more conditional tag like is_category. For example mine is: