I have been using jQuery with DotNetNuke for a while now, and was very happy to finally see it integrated into DotNetNuke. What makes me wonder, is that there is no central method for including it in DNN 4.9.1. The library has been placed into the folder ~/Resources/Shared/scripts/jquery, but the one usage I could find does not use the ClientScriptManager to include the script. Instead, it manually creates a Literal script control. This will cause the script to be included multiple times, if different controls use it simultaneously. Perhaps this will be "fixed" in a future release. Perhaps adding a method to the ClientAPI for including it would be a good solution for a global include mechanism.