Matt Cutts of Google recently posted a video regarding why and when Google may use something other that your title tag for the search results snippet.
He suggested that the best thing to do is to try to anticipate what a likely user may search for when crafting the title tags. Then this is done then it matches the query and Google is more likely to show your title tags.
He then explained Google’s three criteria for determining your title tag should be used:
(1) It must be “relatively” short
(2) It should have a good description of the page and “ideally”: the site.
(3) It must be relevant to the query.
If these three criteria are not met then Google may choose to use (1) content on your page, (2) anchor text links pointing to the page and/or (3) may also use the Open Directory Project.
Daily Updates with RF Rizwan Farrukh
