Is it obligatory for someone who transmits articles and clips from other websites to mention the source, and is the content owner entitled to be upset if their material is published without mentioning their name or seeking their permission?

The questioner should rejoice in the dissemination of his works that benefit people, and not be saddened by their not being attributed to him. He can fulfill Imam Al-Shafi'i's wish by creating a special page for his works to facilitate referencing them. As for someone who attributes others' works to himself, his action contradicts sincerity, and is considered a lie, an indulgence in what he was not given, and theft. It removes blessings and is worse than stealing money, because it involves infringing upon people's rights, academic dishonesty, lying, false boasting, deception, and a crime against history. Therefore, writers must adhere to trustworthiness and attribute statements to their rightful owners.