Just to add my 2cents, if some copy paste the articles from other sources and put the source at the beginning of the thread will this not count under plagiarism ?
That makes it more obvious it's not your own text, but it's really up to the Mods.Quote
As far as i know anything which is copied from external sources (not translated only word to word copy) should be put in a quote, am i right about this 
That's what I would do, or you can use quotes. Example: Satoshi said: "Banks .... lend it out in waves of credit bubbles with barely a fraction in reserve". It's obvious this is a quote, but less disruptive than putting this short text inside quote tags.