I'd like to be able to give each article an additional attribute. Not sure if I can use the columns that exist in #_content. I'm concerned any modifications I do will be overwritten or cause errors. Is there an existing column in the table that I can use?
This sounds exactly what the new custom fields (com_fields) are for.
(Content > fields)
If these don't work for you, can you expand your question to explain what you are trying to do differently.