The reason as to why remains unclear.
Nintendo has asked Icon Games to take down their WiiWare sales numbers, Icon's head of development Richard Hill-Whittall noted in an editorial for Gamasutra.
Previously, we reported that Icon Games had released their sales numbers, which included numbers for their WiiWare efforts. Since then, Nintendo demanded Icon Games erase those numbers from publication.
No reasons as to their reasoning were given, but Nintendo does not seem to allow the publishing of sales numbers even by the games' own publishers. The numbers had shown that sales of their WiiWare games were considerably smaller than those of other games on other systems (which include PlayStation Network). Hill-Whittall noted that while Nintendo is not the only party with this policy, they seem to be "by far the most draconian in enforcing it." He then explained why he thinks such a policy is harmful, particularly to indie studios.