I've downvoted this node because:

• You're using two nodes to ask two questions that could be easily unified
• I'm not naturally diffident, but your questions have the structure of a test or of a homework
• Yes, Perl could be a great choice to develop online forums. If this is your intention, tell us about your projects and you'll find a lot of monks that would be glad to help you. But don't use Perlmonks this way: it doesn't add value to this community and will lead you to a lot of -- :)

see you