You can only do this is the permission of the copyright holder, who is either the poster or the website (check the individual web form or magazine to find out who owns copyright): the copyright holder has the sole right to reproduce, publish, adapt, etc. the copyrighted material; and anything written by someone will be copyrighted, by either him/her or the forum/magazine/etc. in which he/she is published, unless it is specifically placed in the public domain.