Traffic exchange links on ptc sites

Tweet

Im a member of a few PTC sites and I noticed that in the earning area they have traffic exchange links you can click. Im not quite sure what they do, it says for every 5 links you click you get 4 hits, Im new to ptc and dont understand what this means, do you need to have your own website for this to do anything, or do you need traffic with ptc sites? Can anyone explain this to me? I dont have my own blog site/website so is there any point in me having traffic? Thank you to anyone who can help me!