This photo book cover places the text announcing the year, right at the horizon line. The text becomes more and more opaque as it gets to the last digit. If you wanted to be even bolder, you could make the transparency/opacity even greater or use a gradient tool in Photoshop or InDesign to achieve a more seamless look.
The cover title in this case, balances out the subject who is in the lower left corner of the photos. Plus it really draws attention to the horizon line – which I find so appealing in beach photos.