Every institution, be it an institution of the state or one that is privately owned, gives executive decision making powers to individuals within it. For example, a company CEO will have executive power over the high level direction of the company, and a police officer will have the executive power to issue fines on behalf of the state, for certain minor offences. When an individual uses the executive powers given to them in a way that undermines the institution but benefits themselves, it is known as 'corruption'.
There is corruption in every institution in the world, but it does vary greatly by degree. Some countries are known for high levels of corruption in all institutions, while others are relatively low. Since the health of institutions is so important for the functioning of society, the presence of corruption has a huge impact on regional prosperity.
There are a few factors which appear to have a large impact on the presence of corruption.
The Steem Network is a decentralized autonomous organization (DAO). It is an institution. The healthy functioning of this institution, the value of it to society and to stakeholders, depends on low corruption like any other.
Witnesses are granted the most executive power in the Steem Network, the ability to produce blocks (and therefore the ability to censor transactions, at least with consensus of other witnesses). They are not the only ones though, every stakeholder in the network (and thus every account holder) has some executive power. We all have the power to elect witnesses and we have continuous decision making power over the fiscal budget. Every time we make a vote, we have the opportunity to be corrupt. We can vote to benefit ourselves, we can vote to benefit our close friends or we can vote to benefit the network. These aren't mutually exclusive but they are frequently in opposition.
What is unique to Steem is that every user action is transparent to all. Those who engage in corruption must do it in the light of day, and may be forced to justify themselves to the community where otherwise they would have only the easier hurdle of justifying it to themselves.
Corruption undermines institutions. Steem is an institution that can be undermined by corruption like any other. We all have the opportunity to be corrupt, but we can also work to make Steem less susceptible to the problems of corruption. In order for Steem to succeed, we will need to recognize corruption, not allow it to become the socially accepted norm. We need to hold those who engage in it accountable. In the end with a more valuable network and a more valuable token, everyone will benefit from minimizing corruption.