This helps skimming immensely. They also make good link text, helping the reader know what they will get when they follow a link. The design of the page and how it is read will determine whether you use a short title, or a longer summary. Titles can be scanned quickly with the eye. Summaries take more thinking.
Short titles work well Try to keep the titles short, for example, as two to seven word phrases.
Think like a headline writer for a serious newspaper with articles one column wide. Lots of examples on this site This site is filled with many other examples of titles.