CGI vs Servlets

[Pradeep bhatt]

Hi,
I know that there are several advantages of using servlets such as performance(CGI uses process for each request),platform independence and security. Also using CGI requires more understanding of the inner working of web servers.
But there are sites which use CGI.(Javaranch uses CGI if i am not wrong).My question is
what makes these web sites go for CGI. Is it beacuse if some one knows c or PERL why learn java or some thing else?