I'd like to comment on AlbanyYEM's post:
I agree, I love your 1996 analogy, it is what I've been trying to grasp myself. We only need to look at 1995 as a springboard backwards into 1996 through one song: Free.

When Free first came out (and I'm thinking of the Charleston fall 95 version), it had even a slightly different lyric with "the ship goes sliding by" versus "as we go sliding by." The jam section had no major funk bass breakdown by Gordon and instead had insanity layered on top of evil doom. The chords modulate by half steps and its down right sinister...and I miss it ever so much.

But then, Billy Breathes was released, and that was the turning point. When I listened to Billy for the first time, I couldn't even express how disappointed I was. Especially in Free, and then hoped it was just an "album version" and would not be like that in concert...but it was and still is exactly the same, 17 years later.

How were they able to take such an amazing song (and Free comes up in discussion from time to time on the websites) and change it into a vehicle that has no good chances for exploration? The same thing happened to Black Eyed Katy. Again, what a spectacle!!! If anyone was present in 97 for a live performance, you know what I'm talking about. We got it for the first time in Winston-Salem that fall and didn't know what was happening. We were close enough to see Trey literally looking at the crowd with the expression of "they don't like this, I wonder if they think this is cool" because no one was moving, dancing, head nodding, etc. We were so into funk at that point (p-funk, james brown, etc.) that we lost it. By the end of that jam, the Trey peak was full blown and it tore the whole place down...and it was like the 3rd song into the show.

Why did Black Eyed turn into Moma Dance? Same as Free: compartmentalization.

AlbanyYEM points this phenomenon out so clearly, thanks for doing it so well. We expect catalogs of music to be delved into, and poured out with accuracy and clear direction, literally at every show. A girl behind us at first night ATL this summer almost got in a fight with me because I was getting down so much to Possum, as were the two cool guys next to me. "Seriously?!?!! They've played this like 6 times this tour!!" As I said to those dudes after Page's beyond sick solo (how often does Page solo on Possum????), "Possum never gets old." They agreed with violent hi-5s. Well, we need a raging possum more often than not, right?

Here, Possum has a standard structure, no type II going on much. We say that for most of the other songs with big jams. But the boys haven't written new songs with big new platforms for exploration..have they? How about Light? Has it fizzled out and gone dim already? The boys play a less-than-stellar version here at Dicks and it's like people think the song is done already, based on what I've read so far online. Did they blow their improv load during nite 1, or nite 2, or during the Chalkdust???

As a musician, it takes a certain "something" to trigger taking a chance that you will like. It's even harder to predict if your bandmates will like it too. Plus, playing music as intensely as Phish takes a lot out mentally. Sometimes the best idea you have all day, or all week, is played in the first 10 minutes, sometimes before the guitar player is even in the room. That spark is there, and its not fizzled by breaks in tours, or between shows, or a 3 week break before a 3 day weekend. I think it has to do with atmosphere, intention, nerves, and time. What do they say to each other backstage before set II? Those words could change not only the rest of that show, but the rest of the tour.

To wrap up my unnecessarily long post (too), 2012 brought us some big new experimental stuff within new(er) songs, like the Joy songs. It also brought us some very exciting stuff from old(er) songs. But there were stretches of sets that weren't the greatest or most exciting; same goes for shows within last year's tours. But this year, were those same songs as present and as exciting for us all? I heard so much about the MPP Stash and Toronto Disease from this year, but how do these performances rank to last year? Is there anything new they can do with the catalog of songs? I think Albany YEM says it best about the "kind" of jam, be it ambient or cow, or whatever. I'd like to weigh in with maybe a kind of jamming that is going on now.

It's not like a jam that is a medium for Trey to play a string of related melodies, or his harmonizing with Mike in spur of the moment moments along the jam's way. Trey is playing a LOT of complex chords and looks to me like he's trying out new chord voicings even, while improving, and it happens like 12-15+ minutes into a jam. Tahoe Tweezer, during second night Chicago, ATL, Dicks Chalkdust (there are a few other shows, can't recall exact songs or nights, recalling from what I've seen live and on the couch) has these moments. It's very original and I can't remember a time Trey was really relying on this kind of playing during big time jams. It's like writing a song in the Barn with the comfort of his friends, not sure if the chords will mesh with the piano, but they do, and I think this is what is catching people's attention in 2013.

Maybe this is the way Phish will be jamming, like a collective improv song forming/writing type of jam?

Yes, after 96 did come '97, and those cow funk shows came with them. Who knows what their new album will bring?