Our troupe is having trouble interpreting the Correspondences rule. We've got two basic questions (though one is in multiple parts):
What exactly does "associated with the magus's research or reading" mean? Specifically:
a. Does the correspondence have to be something that the magus is working on in that exact season, or just something generally related to his main areas of interest?
b. If it does have to be something that season, what counts as "research"? Anything in the labl What about setting up a lab or adding Virtues to it?
c. If the magus is not doing any research or reading in a given season, does that mean no correspondence is possible in that season?
Does the description of binding the correspondences between two magi imply that their letters (at least, if they're to be bound) all have to be on a single topic? Obviously, if the two magi can only correspond on something both are working on that particular season, it's very unlikely to have 8 straight seasons on the same topic.
My take on it for an upcoming PbP campaign is that the two magi need to establish a correspondence on a particular topic. It can't be little snippets here and there in love letters. This may take a couple letters to settle on. It can be any Art, Spell, Effect or Skill as long as it's theoretical and instructive. And it has to be with an NPC.
As long as the roleplaying is good, I say give them the XP. If they're just doing it to maximize, then channel your inner internet creep in the letters to them
And yes, I would think that if you're going to bind the letters together, they should be on the same topic. But that's my opinion.
You could see this as a free xp every season, with the same restriction on placement as the regular xp. Of course, this doesn't quite work for bound correspondences, but since seasons are not seasons... As long as the activity of interest could be spread across the year, you could consider that all correspondences is associated with that activity.
Using that interpretation you'd need to study the same subject 1 season in 2 consecutive years to create a bound correspondence, and apply all 8 extra xp to that subject. Not that RAW supports or infirms that in any way.
Ok, let's think about what exactly correspondence is... At the simpliest definition two (or more) magi are exchanging letters. However, to be useful these aren't "hi, how are the wife and kids" letters. They are academic correspondence. Academic correspondence is writing out your thoughts and ideas about a topic of study or research (which helps you to clarify your thoughts about the subject) and getting letters back which contain the thoughts and ideas of your sodales on the same topic. On a very practical level it is a debate or discussion in writing. As letters pass back and forth, each correspondent gains a little more insight (both from his own efforts of writing his ideas down and from his sodales' input) into the topic being studied, represented by 1 extra experience point.
To answer your specific questions.
1a) I would say yes, to gain an experience point it has to be something you are actively working on this season. Essentially, the correspondence is acting like a gloss, clarifying and expanding on the topic being studied, and so adding 1 to the study total.
1b) I would say research is any activity that generates a study total... even if it is just Exposure. So, setting up or enhancing a lab can still be a subject from correspondence, albeit only to enhance the amount of Exposure exp gained.
1c) I would say that magus can participate in correspondence, but he might not gain any immediate benefit from it. This raises the question, do all partipants in the correspondence have to be researching or reading about the same topic? Could a magus respond to a sodales' letters, providing his fellow with extra insight while gaining none himself because he is engaged in study of another kind? I would say yes, provide he has some knowledge of the topic at hand.
2) Yes, because they form a single tractatus on that Art or Ability. However, I would submit that they don't have to come from 8 consectutive seasons. It is possible, even likely, for two magi to correspond over a span of decades or centuries, discussing different topics but often returning to the same subject (especially if they are both specialisits) Every 8 seasons out of that represents a single topic could be collected into a tractatus, provided they can be assembled in order.
1, same basic subject. So if the correspondence is on Ignem, the reading or lab work must include Ignem for it to be worth something.
To a large extent, due to 1c, we´ve been very loose on the specifics of the requirement, otherwise it just gets silly. Because yes that´s what RAW says. So if 2 magi are corresponding, by RAW they can only actually read and understand it in the seasons they´re actually working on something vaugely similar, as i said it gets ridiculous.
As long as the subject is something the magi is spending at least some time or effort on, i say they can do useful correspondence on it.
On 2, unless i missrecall badly, it never talks about consecutive seasons, but refers to consecutive pieces of correspondence. Ie, you need 8 seasons worth of consecutive correspondence for it to make sense and be useful.