Let's say you have a 2000 reputation score in the java tag. If you vote on a question/answer that also has the java tag you have the same influence as someone who has 0 reputation in that particular tag.
If the purpose of Stack Overflow is to find the best questions/answers then a pure democracy isn't the best way to do it. Everyone can have an opinion, but those who have contributed more will probably have more valuable or better informed opinions than new or inexperienced users.
[java]
reputation on questions tagged[swing]
, but my vote would still count for more on questions tagged[servlets]
, which I may know nothing about at all. (Assuming they're both also tagged[java]
, for you non-Java folks.)