The title of a document has two roles, to give a compact summary and to lead the reader to read the document. Conventional title generation focuses on finding key expressions from the author's wording in the document to give a compact summary and pays little attention to the reader's interest. To make the title play its second role properly, it is indispensable to clarify the content ("what to say") and wording ("how to say") of titles that are effective to attract the target reader's interest. In this article, we first identify typical content and wording of titles aimed at general readers in a comparative study between titles of technical papers and headlines rewritten for newspapers. Next, we describe the results of a questionnaire survey on the effects of the content and wording of titles on the reader's interest. The survey of general and knowledgeable readers shows both common and different tendencies in interest.