Less is All
Website owners who sell online rely on web surfers finding their pages through organic searches. The title of a page is less important nowadays with the advent of structured-data markup ("rich snippets"). But it still matters a great deal, and the rules have changed. The so-called "long-tail title" clings to a stubborn fan base among many SEO consultants. My own experience leads in the opposite direction.
Whenever I build a new site with the SEO built in from the ground up, I closely regulate title length and I check it in Google Webmaster Tools. Webmaster Tools will list all pages that have titles Google regards as too long. When Google flags something, Google means business. This system is their way of discouraging brazen keyword stuffing. It's not possible to stuff a mile of keywords into 55 characters. Those 55 characters are now the optimal length of a page title, for the purposes of organic SEO.
For Best SEO Outcomes, Keep Page Titles a Shade Under 55 Characters Long
The number though is a little elastic. If your title has lots of skinny letters, you can probably get away with pushing the limit by 3 or 4 characters. Comparing the performance of some of my older, longer titles to my newer, pithier titles, it's no contest: Less beats more every time.
What About Words?
Now let's talk about not characters, but words. Within the character length limits, how should titles be worded? In a word, simply. The title should be written as a gem-like label for the page content. If you are geographically targeting your SEO like me, you need room to add the name of your target community or region.
The content of this blog post is all about optimizing page titles for better SEO. I want Google to display the page in my regional market, metropolitan Milwaukee. So I come up with: "How to Optimize Page Title Tags | Milwaukee SEO Services." I like that a lot because it's only nine words, 55 characters. There's a 98% percent chance that Google will display it exactly as I wrote it. Some practitioners would advocate inverting the hierarchy to read: "Milwaukee SEO Services | Optimizing Page Title Tags." But my seat-of-pants experience indicates it's better for the title contents to flow from the specific to the broad.
What Happens to Violators?
There's no conclusive evidence that Google punishes run-on titles. That would only happen if the run-on title were stuffed with blatant, irrelevant keywords. The price you pay is more indirect, in the form of less control over how your listing appears. In the best-case scenario, Google simply truncates the title. So if your important words are front-loaded, the title will still look pretty good and be seen by the user as clickworthy.
But in many cases, really bad things happen. Google will write its own title to replace your long-winded one. Chances are, the robo-title will have very low clickworthiness. The end result? Yes your page gets listed, but it's going to get less traffic. Less traffic means a lower overall Google ranking for your website. The stakes here are much higher than you may think.
This piece has interwoven my own first-hand experiences with knowledge gleaned from other thought leaders around the Web. It's been a very hot topic among SEO people for the last nine months. To drill down deep into this subject, I recommend Dr. Peter Meyers' post at moz.com.