Minimum wage is a very broad term and it's value depends on your country IMO (for my country I guess the minimum wage for a government personnel is ~$30).
Of course there are people making much more than that in normal occupations but for anyone else if you actually get used to earning online it can be a pretty nice extra income.
Well obviously it depends on where you live. However, rather than wasting time here one could spending it picking up new skills. This could open up new doors and enable you to get a higher pay.
Let's take an example of a signature campaign.
I've used DA DICE for this calculation (potential bonuses have not been factored in).
The current rate for a Hero member is 0.0015 BTC per post with a maximum of 100 weekly. This equals to 0.15 BTC weekly or ~33.3$. DA DICE would only reward you for your usual posting, however you'd have to be careful because of the required quality.
Bit-X Campaign
The current rate for Legendary & Hero members is 0.0013 BTC per post. This campaign has no fixed maximum number of posts, however it has some other limitations (excluded sections/threads).
If you make 100 posts in a day that would earn you 0.13 BTC which equals to ~28.8$. However it is almost impossible to make 100 constructive posts in a day, especially with the limitations of the campaign.
Doing 100 posts a day will
most likely get you banned.
Unless you're from a very poor country (e.g. The Gambia, Liberia, Cuba, Malawi, etc.) that provides very low salary e.g. under 2-3$ a day, it is not worth it.