This is something I’ve been trying to get a handle of. The 30 minute rule applies here too from what I understand. (Welcome to correction)

If you upvote yourself before 30 mins, you basically take all the curation reward for yourself. Afterwards, it is the same as usual. I would assume that your upvote also goes into the pot for curation reward, so it does help others? Generally, I read that it was not frowned upon, so I’ve started doing it myself.