I gleaned the following from PUBYAC. If you're a member check out the archives for 3-27-2009. Please add your own thoughts on the subject. This is just one perspective, if you want to focus on early literacy then be sure to point out the skills to the parents/caregivers so they make the connection.

See also:  https://www.alsc.ala.org/blog/2014/09/storytime-what-is-it-good-for/

We don't use the storytimes to teach, to push literacy, etc. They are purely for fun.  The same goes for the summer reading club.  My philosophy is that if the kids learn to see the library as a fun, happy, welcoming place, they are more likely to want to visit it.  When they visit it, for whatever reason, they inevitably find books to read.  My end goal is to help kids learn to read for fun, but I have found that the didactic approach doesn't help further that goal - the kids get enough of that in school.   When it comes to storytimes, I am simply an entertainer.  I become a librarian again afterwards.  We check out a lot of books following the storytimes, so that approach seems to be working. (PUBYAC 3-27-2009)