Is it permissible to earn money from Islamic and other websites and forums, or does that fall under associating partners with Allah (shirk) in actions, and does shirk occur by associating people in the intention of an action?

It is permissible to take money for work on non-Islamic websites and forums. As for Islamic websites, the default is that working on them is an act of worship. However, the preponderant opinion is that taking money for it is not forbidden if it comes from the public treasury (Bayt al-Mal) or similar sources, or if the worker is poor and in need. Examples include teaching Islamic sciences, teaching the Quran, issuing fatwas, leading prayers (Imamate), calling to prayer (Adhan), and washing the dead. Some scholars have held that it is permissible to take a wage for calling to prayer if one is poor, but not if one is wealthy, and they extended this ruling to all acts of worship.