You will find a link to this 12-page guide here (12 pp, PDF).
It will explain some of what librarians and other data users need to do to provide
quality service for ACS data, including:
* "Cherry-picking" data from different surveys - a bad practice
* Questions of currency versus reliability
* Adjustments for inflation
* Comparing ACS multiyear estimates with each other
* Comparing ACS data with Census 2000 and Census 2010 data
* Four types of sampling errors
* Four types of non-sampling errors
* Data Swapping
* and more
May you find it useful.