add extra explanation

git-svn-id: https://plugins.svn.wordpress.org/dpabottomofpostpage/trunk@988140 b8457f37-d9ea-0310-8a92-e5e31aec5664
+ more explanation

git-svn-id: https://plugins.svn.wordpress.org/dpabottomofpostpage/trunk@988143 b8457f37-d9ea-0310-8a92-e5e31aec5664