Perhaps this new question deserves a separate thread... Adding to Linguoman's examples, here are some other ones, where I tried to avoid injecting the verbs into an equivalent English phrase:
"Покупатель раднеожиданной скидке" = "A customer is happy with an unexpected discount".
"Профессор обрадовалсяхорошей работе студента" = "Professor is pleased with the good job done by the student". Though "доволен" could be a more precise translation for "is pleased with".
"Цветы радуютсятёплому Солнышку" = "The flowers are enjoying the warm Sun".
"Здесь вамне рады" =~ "You are persona non-grata here".
In general case, construction "<subject> рад/радуется <object-in-dative>" means that the subject is experiencing the emotion of happiness, and this emotion is caused by the object. In other words, the object is the stimulus for this emotion. Not only "рад", but similar predicates "радоваться", "обрадоваться", "порадоваться" could be used in such construction, and would always use dative.