PobTalk works as follows:
Every user who comments on the post will receive a number in order of arrival to the new post.
Random numbers are drawn, and the winners receive a vote from my account with the weight of the percentage that received the prize. In your case it was 22%, which is something close to 3 POB.
All this for free interacting with others in the publication.
There is also a way to take a chance and try for a 100% vote in a draw. Just send POB to @vempromundo.pob account and you will be participating in numbers of days for the amount sent. For example if you send 5 POB you will compete for 5 days.