I started playing nl2-7 a few months ago and thought I'd post some of my general and specific thoughts on the game -- I can't say for sure everything I think is correct, but it's worked reasonably well for me thus far.  I'm going to start out with a general introduction since some people who end up reading this (hopefully) may not know anything about the game.

No limit deuce to seven single draw lowball (SDL), also known as Kansas City Lowball (KCL), or just “deuce” is a 5 card draw lowball game with a two-street (predraw and postdraw) structure.  Aces are high only, straights and flushes count against you, so the best hand (which is often called a #1 or a wheel) is a 75432.

Note 1: In lowball games we always read the hand from the highest ranking card down.  Beginners often get confused by this concept.  But to give you an example, a 23459 (which lowball players will read as a 95432, a “smooth” 9, a ninety-five, a 9 perfect or a #19) is a worse hand than a 34578 (which we would read as 87543 and call a “rough” 8, or an eighty-seven or a #13).
Here are a few more examples:

8d9h2s3d4s vs. 5d7h9s6d4h -- 97654>98432
As2h3d4d5cs vs. 2d2c3s4h5c -- this one confuses lots of people at first, ACES are HIGH ONLY, you cannot make a traditional wheel, therefore A5432>22543
7d3d4d5d2d vs. KdQsJc9s2c -- the hand on the left is a wheel in this game, unfortunately it's all diamonds, KQJ92>75432sssss

The game is normally played somewhere around 7 handed and there is a small and big blind to the left of the dealer button just like in unlimited texas hold thems (UTG MP HJ CO BTN SB BB).  However, when this game is played live, the vast majority of the time there will also be antes, usually on the order of half a small blind to induce action.  Obviously, the size of this ante will impact how we play to some degree, as we need to play looser in high ante games and should be more reluctant to get in unnecessary spots in low and no ante games (this is true of any game involving antes).  On pokerstars (the only site I’ve ever played on that offers this game), no ante is used in the cash games (though it does appear in the tournaments and sngs they run).  Live, this game pretty much only runs at fairly high stakes (at the commerce with Billy Baxter they play something like 200/400/100, occasionally at the Bellagio during WSOP time and as part of mixed games).  There is currently a $1500 and a $10k bracelet event at the WSOP.

Note 2: Because NL2-7 is a two-street game, games tend to play shallower than NLHE.  In order to play 100bb pots in NL2-7 (particularly with no antes) there requires (or should require) a large degree of cold-decking (or higher level aggro play).  I’d say something on the order of 50-60bb is going to be a typical buy in size, with most medium sized pots being in the 10-20bb range.

Note 3: Unlike NLHE or PLO, hand equities in NL2-7 DO NOT run that closely together.  It’s not uncommon to be drawing dead or have your opponents drawing dead before the draw.  This both gives us disincentive to play marginal spots (when calling and more so when OOP) and sort of as a corollary to apply more pressure on those who are calling and are OOP.