Ruth Burr, the lead SEO at SEOmoz put out an interesting article, suggesting that shorter title tags may be more important in Google these days. SEOmoz was finding that some of its posts with longer titles were not displaying the right titles in search results. Rather, Google was returning the keyword-heavy part of the content's URLs as the titles.
"It looks like having a short, search-friendly title tag has increased in importance - without it, Google could replace your title with just about anything, including part of your URL," she concludes. "This doesn't exactly create the user experience we want, and a replaced title tag is a lost opportunity to encourage searchers to click."
We've been unable to reproduce these kinds of results. We've had some pretty long title tags, but they don't seem to be affecting the results in this way.
Here's an example of a title tag, and the way it shows up in Google:
Google talked about page titles in search results a bit on its Webmaster Central blog earlier this year. I'm not sure it helps to explain much about this exact situation, but it does provide some insight into how Google handles titles:
We use many signals to decide which title to show to users, primarily the <title> tag if the webmaster specified one. But for some pages, a single title might not be the best one to show for all queries, and so we have algorithms that generate alternative titles to make it easier for our users to recognize relevant pages. Our testing has shown that these alternative titles are generally more relevant to the query and can substantially improve the clickthrough rate to the result, helping both our searchers and webmasters. About half of the time, this is the reason we show an alternative title.
Other times, alternative titles are displayed for pages that have no title or a non-descriptive title specified by the webmaster in the HTML. For example, a title using simply the word "Home" is not really indicative of what the page is about. Another common issue we see is when a webmaster uses the same title on almost all of a website’s pages, sometimes exactly duplicating it and sometimes using only minor variations. Lastly, we also try to replace unnecessarily long or hard-to-read titles with more concise and descriptive alternatives.
Matt Cutts talked about snippets in titles in a video a few years ago:
As Barr notes, some of Google's algorithm changes for the month of May had to do with how Google handles titles as well. These included:
We talked about these a bit in the article: Google Calls Upon Tom Waits and Otis Redding To Help With Your Site's Titles.
Barr's advice is to use short, but keyword-rich titles in title tags, even when the titles themselves are longer. She's even going back on "years of posts" and adding shorter titles.