What is the ruling on being named in forums with names such as "Astaghfirullah (I ask Allah for forgiveness)", "Subhanallah (Glory be to Allah)", "La Ilaha Illallah (There is no god but Allah)", and "Alhamdulillah (Praise be to Allah)"?

There is no harm in entering forums while seeking Allah Almighty's forgiveness, glorifying Him, or remembering Him with any type of remembrance. This is like someone who begins their speech with "Bismillah" (in the name of Allah), or with praise and glorification of Him, and with prayers and peace upon the Messenger of Allah, peace be upon him, and concludes it similarly. This is permissible because it involves reminding, advising, and enjoining good.