I guess it all depends on your intention and the outcome of it in relation to the community here. We don't allow posts here that link to other discussions for the purpose of debate, defense, gang-up advocacy, etc. as it creates cross board issues for our community that is often played out on the boards here. So posting things at another site about other MDC members and MDC discussions to stir up a pot here or there is not appreciated.
As for quoting someone's post I suggest you read up on copyright issues in this regard. Most people would appreciate you seeking their permission first. Some people will complain loud and clear to your host.