Do I have to select my encoding in preference?

Yes. The unidoc blog system use UTF-8 (universal character set) to present author's publication. The encoding preference is only for the editing purpose. In another word, an author who uses GB2312 simplified Chinese should indicate his encoding preference so that his work can be properly converted into UTF-8 in the final publishing stage.

How about using UTF-8 as default encoding?

UTF-8 is convenient for you only if you can input UTF-8 code directly. For example, the English is automatically in UTF-8. But if you are using input method (IME) to enter text other than English, most likely, you are not using UTF-8 and you must tell us your editing encoding so that we can perform the UTF-8 for you correctly. So, unless you are English user, please let us know your encoding.

What is the difference between delete and archive?

Deleting an article will remove its database entry, and the XML file if it is already published. Archiving an article will also remove any published XML files, but it only labels the corresponding database entry as archive. Archived article can be retrieve directly from database.