I love Wikipedia. I use it several times every day. All of mankind working together towards a common goal - creating a complete encyclopaedia containing most of our knowledge.
There is a problem. Wikipedia is often considered to be the truth. So, having control over a certain set of Wikipedia articles gives power. Since Wikipedia allows you to hide behind a pseudonym your motives for editing the article might be very well hidden. Wikipedia tries to counter this by settling conflicts of interest in the appropriately named "conflict of interest board". This is not enough. First of all, a conflict of interest is really hard to spot if you don't know who has written the article. An unsuspecting journalist might run a background check on some topic and may be given a bias towards a specific topic. An controversial figure running a whistleblower campaign again some powerful entity might be smeared by an article making him pariah to the press. The Register ran a story which illustrates this well.
Secondly, there has a least been one account of people in the board having a conflict of interest themselves (see this article on The Register) making resolving the conflict rather difficult.
As long as Wikipedia allows editors to hide behind a pseudonym in cannot be considered a credible source for controversial topics. Wikipedia must change and become more transparent.