Interestingly, 1. e3 is the third most played move on chess.com according to the Game Explorer: http://www.chess.com/explorer/index.html?db=2

Since when did e3 become popular?  I suppose one could play a reverse French Defense (1. e3 e5 2. a3 d5 3. d4) or a game could transpose into a queen's pawn opening with 1. e3 d5 2. d4.  Can anyone shed some light on this?

I checked it out. Black's most common response is 1...e5. After that, white's two most common second moves are 2.Qf3 and 2.Bc4 (while 2.Qh5 is 5th most common). So, it seems that the majority of games beginning 1.e3?! are games where white is played by a beginner going for a variation of scholar's mate.

Other things of note here: with 1.e3?! black wins 57% of the time - and if black replies 1...e5 or 1...c5, black wins almost 2/3 of the time. Even if you look at master games beginning 1.e3 black wins amost 50%.

Why would anyone want to open like this? I don't know. Seems like at best it just wastes a tempo, since white normally wants to play e4 at some point anyway. Although I guess you're right that it could transpose into some 1.d4 opening. But then, why not just open 1.d4 in the first place?

my dad played 1. e3 at 2200~ level twenty years ago.  he used it to transpose into a colle or stonewall or queens pawn game, and tried to confuse black on the first move with it.  i think he did it mostly as a novelty though, he usually opened 1. d4 and then played e3 later. 

 

i really cannot believe e3 is the third most common opening on this site though.. 

1. e3 is a flexible move, either intending to go a move behind and play into a defense with the White pieces, or to give more leverage to a d4 or f4 advance, or even play Nf3, or b3... there are a lot of options.  It is a bit of a waiting move, yet it is totally playable.

I think a lot of beginners would play it and higher rated players might play it to get their opponents out of their comfort zone. It can easily transpose into a d4 opening and can lead to interesting non theoretical positions. I know someone who always plays a3!? followed by c4 usually leading to a reverse sicilian but playing a3 first raises blacks blood pressure as it looks like a patzers move.