The folks at RankRanger are showing data that on average, the title snippet length shown in the Google desktop search results have gone down from 55.3 characters to 50.9 characters on average.
Of course, Google title length is purely dynamic and can show at different lengths based on tons of factors. But on average, it seems the average length of the title has dropped by almost five-characters.
Mordy Oberstein from RankRanger posted about this on Twitter and here is an updated chart from their tracking tool:
Just to be clear, Google doesn't really like talking about the length of its snippets. So we won't be asking them about this change. It won't go anywhere.
In short, you can use whatever title tag or meta description length you want still. Rankings won't differ with this change. But your click through rate might.
Forum discussion at Twitter.
