In many article the poster presents a question, or in some cases more than one question. I think the record for most questions in one post is probably about eight. Posing so many questions at once can make responses awkward. With multiple questions to be answered, a response that does not explicitly mention the particular question being addressed can become confusing.
For this reason, posts that pose multiple questions will be re-written to explicitly enumerate the questions, marking them with prefixes Q1, Q2, Q3, and so on.