Surely. IMHO, FWIW, YMMV, etc.
Actually, there are (were) two possibilities in my head :)
1) It's a local university's IT department and they're advertising their cryptography course or some such. For a couple of messages, I thought this was the most likely source of the messages. Now, I really don't.
2) It's Bollycat and Spingolly teaming up, possibly with another couple of people - I've noticed those two have, what a cynic might consider, "slipped up" a couple of times when it comes to either finding the message or decrypting it. I think it's just for a bit of fun and to stir up interest, etc
My personal opinion - and that's with nothing leading me towards it - is that a group of friends were fascinated by Cicada 3301 and have tried to create their own version. Frankly, if it ever gets to the point where there's a link to a web address of an image that ends up being some stenography, that confirms that. I'm surprised they haven't gone there yet, honestly (I wrote this BEFORE the latest "finding" on stenography).
I think their motive is as simple as fascination with 3301 et al and maybe they wondered how long they could keep interest in a reddit-based puzzle going. The other alternative is mental illness, but I grow increasingly sure that it's part of a collective and it's unlikely 2+ people have the same affliction.
The messages aren't really part of a common thread (at least, not one that's obvious), which makes me think it's a small team of people doing it and they don't really have a particular end goal in mind. I think they're composing the messages similar to how screenwriters write TV episodes (a week or two before they air, based on feedback from Nielsen).
If there is no common theme or purpose, then it's impossible to solve, in the same way it is if it's the product of a mentally ill person (one person in the whole world knows how to solve it - the author).
There is, after all, only one person in the whole of Austin who has seen these - indeed, they were to such lengths that they supposedly risked being hit by a train to get AT the message - spingolly.
You can sort of tell the people who like to solve puzzles from the people who seem to be far too "in the know" - e.g. the random "I found this music video on YouTube" stuff.
There have been a couple of "tests" I've mentioned in my comments to see if they featured in future messages (Fibonacci, etc) and, for the most part, they did.
I also think there are a couple of ... what's the term for it ... fake accounts which might be at play here. There are a couple of unusual terms which have been repeated by different users ("nailed it"), which gave me pause for thought.
These are the same users who don't seem to have much history aside from posting on this subject, FWIW.
Once the gist started to meander towards the bizarre cult nonsense (message 8 or 9, I think), I excluded a local IT department. There would be a final riddle to solve based on every single one of the previous messages. It's how the TLA departments of the USG do it (part is to make you aware that someone intercepting a single message can render communication indecipherable, etc).
But there is no common theme, therefore, it's very difficult to determine a purpose, such as the "final riddle" theory.
As for the "group", I think the members are:
Bollykat - Portland-based, seems to be the main "driver" behind the sub; regularly replies to comments, has a strangely magical ability to decipher and decode typos :)
Spingolly - Austin-local, always there to find the message (I don't think anyone else has found a single one yet, have they?)
NinjaStyleKungFuGrip - redditor for less than a month, pretty much all of their comments have been on the cipher
Stupidface5000 - in CA, but solved some bizarre riddles without too much logic (I suspect this person isn't part of the group, actually)
Praenomenal - I know this is bollykat's friend from Portland, but, honestly, I'm starting to have some doubts about whether he's part of it because of the way he approached that Base64 encoding thing.
Passiflora_incarnata - redditor for a month, only input has been to the cipher. Seems to be able to make incredible leaps of logic and deduce fantastic coincidences, etc
Wwantt - redditor for a month, only input has been to the cipher (yes, this is you, sorry - but, frankly, I wouldn't bet my house on you being in the know about it)
Note this comment in the 13th message. Somehow NSKFG knows that P_I is Spingolly.
[–]passiflora_incarnata 6 points 2 days ago Not sure if any of this is relevant, but 1597 is not only a Fibonacci number, it is the largest Fibonacci emirp, which is a prime number that gives a different prime number when reversed. This may be relevant, as the number 1597 is at the top of the staircase...the number three is the second prime number in the Fibonacci sequence, 2 being the first (and also has the distinction of being the only even prime number)...i wonder if we are being asked to fill in the numerical sequence on the staircase.
[–]NinjaStyleKungFuGrip 3 points 2 days ago Just a Fibonacci Spin, nothing to worry about. :)~~
Those are my two cents, picked up from following the "puzzle" for the last couple of months. I could be wrong, but there are a few other "circumstantial" indications (no replies to messages, etc) which lead me to think there's a 90% chance I'm right.
No offence meant and I'll gladly admit I'm wrong if I end up being!