This is according to a recent post on the e-consultancy blog anyway, and if you read the article it does make a lot of sense. The objective of a title, whether on an email, blog post or web page, is to get your content noticed.
- By search engines
- By people scanning their email inbox
- By social media followers
In all these cases 65 characters seems to be optimal. For Search engines – 65-70 characters is seen to be the optimal length for a page title from an SEO perspective For email 65 characters means that there is a good chance that your subject line will be seen in full in the inbox For social media – Especially twitter, it leaves room for links, and most importantly for people to add their comments when the retweet. You will find the full article here on e-consultancy, and it is well worth a read.
