The majority of bounty hunting is not 'work', it's tapping a few keys on your laptop/phone. If you're talking translation or content, then yes, that is work, but those normally pay much better than any social media bounties. As someone already mentioned, these type of bounties are very popular now, so will rarely give high rewards once the shares have been divided. If you want to know exactly how many tokens/coins you will be getting at the end of the campaign, then go for bounties that give a set amount per week/month. The whole idea of bounties is to raise awareness of the ICO/project and attract potential investors. The company needs to ensure that they get value from the bounty, which in the long run should benefit bounty hunters anyway, as the project is more likely to succeed and consequently, the value of the currency should improve. Doubt many people become millionaires by doing bounties (at least not now anyway, maybe last year), but at least can make a bit on the side.