They are frequently the subject of guides and seminars on how to make friends and/or meet people.
Different situations may call for different openers (e.g. approaching a stranger on the street versus meeting them at a more structured gathering of people with like interests).
Judy Ringer's We Have to Talk: A Step-By-Step Checklist for Difficult Conversations points out that an entirely different set of openers may be used for sensitive conversations, e.g. about employee performance, in which a main goal may be to avoid putting the person on the defensive.
These openers often take the form of simple direct statements such as "I have something I’d like to discuss with you that I think will help us work together more effectively".
[3] In sales settings, conversation openers often are used to probe the subject for information.