Readers who want to go their own way will take no notice of promotions. Readers who do take books from displays will make their own minds up about whether the risk was worth it.
Promotion is the key to helping the majority of borrowers who don't know what they want find something they are willing to try. Promotion is often taken to mean large scale special displays, printed booklists and glossy posters, but promotion also means turning books face on, having paperbacks easily visible and taking the time to discuss with a borrower what they might read now they have read everything by their favourite author.
The role of the library is to give people access to books. Access means more than making books physically available; it is empowering people to make choices and take risks across the full range of material. Most of us don't exercise our choices across the full range, we restrict ourselves to what we feel comfortable with. The barriers to taking a risk in choosing a book are psychological; we worry that the book will be difficult or boring, we won't understand it, it's got no story, it might be upsetting or too slow to get into. The purpose of reader development is to address these psychological barriers and open up areas which people regard as closed to them.
How can we make sure we have a range of promotions to tempt different audiences so that no single taste can be detected as dominating?