Hey, narrativeflow. Welcome to the Kitten.
I'll do my best to answer your questions.
1) some fics are not here at all, but still (only) archived on the 'old' board: is that right?
Archived fics are here at this board. When we moved here from ezboard, we made every effort to bring along absolutely every single fic thread. There were a few threads that didn't make the move very well and those were fixed manually. It's possible there are still some threads that didn't come over properly that no one has noticed, but if there are any, it must be very, very few. So, no, there shouldn't be fics at ezboard that are not also here. If you (or anyone else) comes across one, please don't hesitate to PM a mod and let us know about it.
2) some fics mentioned (for ex., in the Recommendation thread) aren't here for different, Unknown reasons (if so, and if hotlinks aren't allowed... uh, any suggestions on ht find them?)
It does happen from time to time that fics are removed from Pens and/or from the archives. Sometimes this is for FAQ issues and sometimes it is the result of a request from the author. Whatever the reason, if a fic is no longer on the board, we won't be able to help you find it. This thread and the recommendation thread are both for fics that are on Pens or in our archives, not for fics that are posted at other sites. For fics posted elsewhere, I can only suggest Google. (The only exception I'm aware of is Lisa Countryman's fics. Because her chapters were so very long, they were always at her website with only a link to her site posted in her threads here. I do not know the status of her fics or her site. Many Kittens have posted asking about her last unfinished fic and no one seems to know anything about it.)
3) there are sub-boards which also have fanfic--but... I can't tell how/in what ways the ff is different: on account of subject, content, author or what.
Fics are in three places. We have Pens for active fics, the Completed Fics Archive for completed fics, and the the Pens Archive for unfinished fics. In order to keep the archive from being huuuuuge, each of the archives is in two parts by author name. There are no categories for subject or content or rating or anything like that. Originally, the first post in each of the 4 archive forums was an author index, but this has been in disrepair for some time and, as it is extremely time-consuming to fix, I doubt it will be repaired soon. When I need to find a fic by a particular author, I just do a Ctrl F on each page. This is cumbersome on Pens, but the archive forums are all five pages or less, so it's pretty easy to find a fic there if you know the author's name or a word in the title.
If you are looking for a fic based on some aspect of the plot or subject matter, this thread is the best place to ask about it.
Is there some thread that helps explains all this? I've read the FAQs & stickies but am still Not Getting It. (Like: is it just a matter of where an author posted first [on what board], in cases of a W/T that's recommended but isn't here--or is it to do with content? or does it just totally depend, on a case-by-case basis?)
All fics are posted first on Pens. As they are finished, they are moved to the Completed Fics Archives. Fics that sit on Pens for an extremely long time with no updates will eventually be moved to the Pens Archive for unfinished fics. All the fics in the recommendation thread should be here. I am not entirely certain what exactly you're asking, so if I haven't answered it, please don't hesitate to ask again.
Also: the Recommendation thread is a nice way to start looking around, but it's kinda brief, and closed now. Could it maybe be reopened, so it could reference stories that are more recent?
The
Pens Recommendation Thread has recommendations for about 40 fics. It is not closed and has never been closed since it was started. It's open to anyone who would like to recommend a more recent fic. But only completed fics can be recommended in that thread. If you are looking for recent completed fics that have not been posted about in the recommendation thread, you should check out the first pages of each of the Completed Fics Archives.
Finally... the various indexes seem a little scanty, relative to the amount of stories that are here: is there some other place I should be looking to figure out ht organize myself a bit...? For ex., if I find someone I like & want to check out the rest of their stuff, it's been hard for me to find a simple way to do that.
Are you talking about the author index posts in the archives? Yes, those posts are messed up and useless. But only the archives had posts like that (Pens does not have any author index or any other type of index). There are about as many fics on Pens as there are in all the archives.
Fic authors writing a series usually post links to the other parts of the series either in the first or last posts in their fic threads. For authors who do not do that, I would recommend using Ctrl F to find for the author's name on Pens and/or in each of the archives. While a bit cumbersome, yes, that should return every fic thread the author has and that is probably the easiest way to be certain you have found them all. Another option is to post here in this thread asking others to suggest more fics by an author or fics with similar themes or subject matter or whatever it is you're looking for.
As a general guide for discovering fics, I'd always suggest starting with the recommendation thread. Perhaps then the completed fics archive or, if you want to read fics that are ongoing, the first couple pages of Pens will probably have the most regularly-updated fics. A thread with a ton of posts and views is, at the very least, a popular fic and also probably a pretty good one. We do have many, many excellent authors.
I hope I've been able to clear some things up, but please don't hesitate to post again if you have further questions. Welcome again and happy reading!