Apparently DDR Max 2 US can "Link with previous games for special features", according to the official Konami site.

http://www.konami.com/Konami/ctl3810/cp20110/si1588394/cl1/dance_dance_revolution__ddr_max_2_greatest_hits

The packages of DDR Max US and Max 2 US also speak of these special features with previous games, but I've never seen or heard of anything more specific. If you know of what these "special features" are please explain? Thanks!

the linking feature is only for Edit Data.

Oh man, for real? That's silly. I thought there was something cool. Bummer.

It also might have to do with the JP versions that can unlock previous Mixes (Max2 unlocks Max, Extreme can unlock both, I think Party Collection can unlock all 3; likewise SN2 JP can unlock SN1). Info gets copy/pasted sometimes.

This would be a great functionality to have in the US versions, though.

Do you mean that it unlocks all songs/courses/etc in previous mixes?  If so, I agree, that would be handy to have in the US games.

Yes, the Japanese games do unlock previous mixes. I have DDR Extreme JP and it has user support in the options section that lets you unlock everything in Max/Max2 JP that you haven't already unlocked. It is a great feature, but I doubt US games would ever get it. Besides they're not as hard to unlock as the Japanese ones, so I hear.

"Do you mean that it unlocks all songs/courses/etc in previous mixes?  If so, I agree, that would be handy to have in the US games."

Yeah, just so long as you already have a save game for that mix on your memory card.

The called "Support" function (1st released in DDR 3rd Mix JP)

the japanese games are LOT harder than US ones.

Support was released in

 (game - support)

3rd Mix - 1st, 2nd, Club Ver.

4th Mix - 3rd

5th Mix - 4 Mix and Extra Mix

Extreme - MAX and MAX 2

Party Collection - Extreme

Festival - Party Collection

STRIKE - Festival 

DDRSN - Strike

SN2 - DDRSN

and so one...

You forgot that Max2 can unlock Max, but otherwise that looks accurate.

yup... I forgot that, due to the JP DDR MAX game... I've been completed the game, when MAX 2 JP comes to the markets. (too easy)

I hope DDRX will have this kind of support.

Oh man, if DDR X has this I'd be happy. Anyone that's lost their file due to corrupted data will buy DDR X just to save themselves the time haha.

I looked into this linking feature on the US games, and it's actually pretty cool. If I had edit data on any of the songs that are on more than one game, I'd transfer them. I don't though, too bad.