The title tag is important for search engine optimisation as it is used by most search engines (including Google, Bing and Yahoo) to rank the content on the document.

Page title is often the first bit of information that people see about your site when searching for a phrase. The title therefore often determines whether the person doing the search will click the link or not.  It is important to provide a clear, descriptive, relevant title in order to weigh the odds in favor of the site.

Main reasons for a good title tag:

1. Almost all search engines use the title tag when indexing your site;
2. The title tag describes the site when someone bookmarks or adds the site to their favourites;
3. The title tag provides the main hyperlink text that links to the site

Make your title 40 to 70 characters long (or 6 to 10 words)  and never, never, never use ‘home page’ as your page title.

The title tag is usually used by Google for the title displayed search results. However, if the site is lísted in the Open Dírectory (Dmoz) then Google may use the Open Directory title unless the "noodp" meta tag is applied

i.e. meta content="noodp" name="robots"

This meta tag tells Google not to over-ride page titles.