Is it possible to use tags in a forum and add afterwards a tag cloud block to visualize the tags?
Not with core Moodle.
https://tracker.moodle.org/browse/MDL-21416 is one tracker item. THree votes.
Thanks. It's a pity but with 3 votes it hasn't much chance to be implemented in the near future.
Thanks for flagging this tracker item up - have added my vote to it.