OK,
Now I understand you.
1- About first question, I considered was not interesting having tag cloud with personal documents, because nobody except you can accessing to your personal documents, and we've not separated personal keyword from others, really there's one tag cloud for all company. Here we've been thinking if could be good idea have two tagclouds, some personals, and others for all company. We've not yet implemented, and it was on discussion last year, without taking any conclusion. I'm opened to listen you about it.
Tag cloud in great installations have some problem too ... too great means not good for end user. So much tag makes it unnusable.
2- About second question. You must register a thesaurus. Then will appearing the closed dictionary keywords. That's the idea, and that's the reason why is empty. Other problem with tag cloud is that dictionary is not controlled, to solve it we added closed dictionary ( thesaurus ). You can take a look here about thesaurus.
http://wiki.openkm.com/index.php/Installation_Guide ( at end )