Wordpress add filter to the_content()
I would surmise you need something like that (if it's indeed a filter callback):
function add_something($content) { return "test" . $content;}Seems what the docs say:http://wordpress.org/support/topic/add-something-to-the_content
you omitted the return statement.
function add_something($content) {echo "test";... change $content ......return $content;}Be advised that if you want to modify the content, you must append it to the variable. Using echo will output 'test' at the time the script is called. It will not append or prepend it to the_content()