I've been wondering this too.
This userThis user has asked a long series of related questions. He's done a tried to make each one specific, separate, and of reasonable scope. As a result, several of the questions have been unanswerable based only on the information given in the question.
Because I've been following the progress of his program from the beginning, I've been able to see the big picture, and answer several of the questions, each time referring back to code posted in previous questions and answers. Now, this is good for me, but the other people answering don't have all of the information. Edit: These linked questions show up in the sidebar, right above the related questions. This should be more prominent, but it doesn't solve the problem of them not being obviously connected until after I've posted my answer.
My Proposal
When a uses asks questions less than seven days apart, suggest they add links to their recent questions if they are related. Provide a list-o-links with checkboxes, and then prepend them to the answer like the Duplicate Question
link. This would make it much easier for people to give complete, helpful answers as they would have more context.
What is the best (and / or official) method for addressing these "ongoing" questions? Referencing previous questions or trying to take each as a separate entity entirely?
Always try and provide a complete answer. If you don't answer a question in context, you're not doing anyone any good. Context matters -- there aren't very many absolutes.
Also, if you know that there is information in other questions, edit it into the question. Even if you don't have 2000 rep, you can suggest the edit.
Edit: From my comment on the other answer, about whether questions like this are "too localized" and don't end up being a good resource anyway:
There are tons of times when new programmers are on the steep part of the learning curve and may get stuck repeatedly on a single program. It's hard for them to explain exactly what they need, but if you can figure it out from previous questions, sometimes you can put together good answers that have the potential to help others in the future.