If the poster is anonymous (hasn't created a wikidot account), you might be able to tell if it's the school itself by looking at the IP address it is posted from. If you go to the History display, the IP address of an anonymous poster is displayed (although the last part is obfuscated). If you take that IP address and run a lookup on it (e.g., using http://en.utrace.de/) and substitute 0 for the obfuscated last digit, you can get an idea of where it's coming from. For example, if I was anonymous and posted from Washington U, the IP would show as 128.252.57.x so plug 220.127.116.11 into the IP lookup. If the anonymous poster was posting about Washington U, you'd know it's an insider (although not the relationship to the search committee). Other than that, it's likely an applicant or friend/lover/pet of the applicant.