Yes you're free to join those social media campaigns. There's no limit or ranking requirement on it for some but there are others that are limited to member+ ranks.
if not then tell me how can I know about the new campaign.
Stay on
Bounties so you can choose the ones that fits you with their requirements, just take time reading their rules.
This is definitely true and go out with the link given and there are lots of bounties which do almost launch up on everyday basis where you wont really worry on where you would tend to join up but basing on your rank you would really only able to join with social media campaigns since it doesnt really have rank restriction and the limit on how many you would able to join out. As long you do able to handle things up then you can join up as many as you can.