Eligibility for being an EXPERT

Hi members. Can anyone tell me, watz d requirement for being an EXPERT... B'coz i've many a times noticed that few doubts in experts' section remain unanswered, while i know the correct answer of such querries. Moreover, i can't reach the profile of asker as its "anynomious"..... And i think same problem may b wid many of non-expert problems as well.... I tried asking same to admin twice, but did not get any response... So please "anyone" knowing the eligibilty of being an expert, do tell me... Thanx a lot....