[We] tested how well users understand the first 11 characters of a website's links and headlines... Users typically see about 2 words for most list items; they'll see a little more if the lead words are short, and only the first word if they're long. Of course, people don't see exactly 11 characters every time, but we picked this number to ensure uniformity across the sites we tested.
First 2 words: A signal for the scanning eye - article by Jakob Nielsen
Jakob is also a fan of the BBC's online editorial approach. In this article he praises the quality of BBC News headlines. His examples and analysis make this worth a quick read.
He says headlines should be:
- short (because people don't read much online);
- rich in information scent, clearly summarizing the target article;
- front-loaded with the most important keywords (because users often scan only the beginning of list items);
- understandable out of context (because headlines often appear without articles, as in search engine results); and
- predictable, so users know whether they'll like the full article before they click (because people don't return to sites that promise more than they deliver).
World's best headlines: BBC News - article by Jakob Nielsen