Here is the all-true story of some intriguing events that have transpired at the MozPlex in the last couple of weeks.

It all started when Jamie wanted to look up his fantastic post from last year, "Custom Reporting Using Google Analytics and Google Docs - The Ultimate Analytics Mashup." Not having the URL committed to memory, he did what any of us might do: he Googled it.

Imagine his surprise (and my consternation) when instead of a useful, keyword-rich, call-to-actiony title, he saw this:

For some reason, Google was displaying the text from the unique part of the post URL, rather than the title. A quick survey of Mozzers found that several of us had seen similar results when Googling old blog posts:

But it definitely was NOT happening on all blog posts!

I'm gonna be honest with you guys: I could NOT figure this out. I checked various factors for correlation. Could rel=author be causing this? Was something happening with the way title tags were being generated on the back end of the blog? Nothing seemed to match up.

One factor that I considered, but almost dismissed, was a change in how titles are truncated. The Google Inside Search blog had just released their monthly list of algorithmic tweaks for May, including these 3 that specifically had to do with how titles display:

• "Trigger alt title when HTML title is truncated. [launch codename "tomwaits", project codename "Snippets"] We have algorithms designed to present the best possible result titles. This change will show a more succinct title for results where the current title is so long that it gets truncated. We'll only do this when the new, shorter title is just as accurate as the old one."
• "Efficiency improvements in alternative title generation. [launch codename "TopOfTheRock", project codename "Snippets"] With this change we've improved the efficiency of title generation systems, leading to significant savings in cpu usage and a more focused set of titles actually shown in search results."
• "Better demotion of boilerplate anchors in alternate title generation. [launch codename "otisredding", project codename "Snippets"] When presenting titles in search results, we want to avoid boilerplate copy that doesn't describe the page accurately, such as "Go Back." This change helps improve titles by avoiding these less useful bits of text."

In short: When your title tag is too long, instead of simply truncating it and adding an ellipsis to the end the way they used to, Google is trying to algorithmically determine a better title for the post.

But surely, I thought, SURELY this wasn't what was happening here. How could a string of words separated by dashes and pulled from the URL be a better title than the actual title? Even a shortened version of the actual title?

My mistake in my initial round of sleuthing was that I ignored Occam's Razor: the simplest explanation is usually the correct one. I tried shortening the title tags and it worked like gangbusters:

What We Learned

Like many blogging platforms, the SEOmoz blog has an option to include a custom title tag. If no custom tag is created, the title tag is generated from the title of the post. We've got some pretty long titles of posts in our library, but many of them had no custom, shorter title - post authors were relying on Google to truncate as needed and focusing more on writing a great headline.

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. This doesn't exactly create the user experience we want, and a replaced title tag is a lost opportunity to encourage searchers to click.

How Long Should My Title Tag Be?

There's a great post that just went up on SEOMofo about how long title tags can be and still be displayed in the SERPs. To sum up: the old rule of "70 characters or less" is no longer as hard-and-fast as it used to be. SEOMofo's experiments show that now Google is truncating title tags based not only on number of characters, but also on the pixel width of your title tag. So title tags rich in wide letters like W and A won't be able to fit as many characters in before getting truncated, when compared to title tags rich in narrow letters like i and t.

We'll need to experiment further to figure out exactly where the limit is on title length/width. In the meantime, make sure your pages with long headlines have shorter (still keyword-rich) titles in the title tags, and be aware of your use of wide characters. In my spare time recently, I've been slogging through years of posts and adding shorter titles as needed; I recommend you do the same.

Update: AJ Kohn has more on this topic - including other reasons Google may replace the title tag, such as relevance to the query - over here.