Wow!

Though I must say, Ivandh was wrong about calling people "idiots" who memorize openings. It was fun for me when I did, and it made me feel that I was getting serious about chess. 

Wow! Indeed. That was exciting!  And of course single games can be significant. When it comes to more obscure variations like the Smith-Morra, clashes between top players are quite rare, so each one of them is a valuable datapoint. 

BTW: I thought the right to call people idiots was one of the benefits of using Chess.com

The best advice I got from the forums regarding opening play is to play the same openings (for black and white) over and over again until the ideas are fully absorbed.  I enjoy playing 1. d4 and honestly speaking, when I initially read some of the ideas behind some of the lines, they made no sense to me. 

The opening book would say: "After x White should play y because that puts more pressure on the centre and counters z".  And those lines only started making sense to me after losing a couple of games and going over the analysis afterwards.  Sometimes by not following the best lines, you are simply opening yourself up to some nasty tactical attacks afterwards.  But you only really see these complications when you play them.   And IMO, if you are serious about improving your play (and openings), analyzing games after you have played them is of key importance.

Themed tournaments with different opening variations are also one of the big reasons why I love Chess.com so much.  I played one game against a friend of mine where I played the Benoni just for fun.  I had no clue what the opening was about and I lost badly.  Out of annoyance I convinced myself it's because the Benoni was just a dumb opening.  But recently I joined a Benko Gambit themed tournament (the Benko is a variation that arises from the Benoni) and I am LOVING it!  Hopefully with some more practice, it will become a very powerful surprise weapon in my arsenal.   Needless to say, I changed my mind about the Benoni being stupid.

I only call people idiots when they're stating things that I know for a fact are false and misleading others. Not people who are trying to understand openings, which as IM Andy Soltis stated is helped by memorizing at least a bit about them.

I learned this very late in the many years I have been playing chess, and it is excellent advice.

I rarely find myself agreeing with uhohspaghettio (or even writing such a long name!) but he's completely right--you need to do a little memorizing to play the openings effectively. Obviously it's easy to overdo it, or to confuse memorizing with understanding, but it's ridiculous to think that you can solve all your opening problems by just relying on "general chess principles." 

People constantly tell less experienced players to forget about the openings and just study tactics, tactics, and more tactics. I think this is misguided advice. We've gone from trying to warn developing players against spending much to much time learning the openings, to pretending that a little opening study is bad in itself. Inexperienced players need some help in figuring out how to open their games, and they certainly want some help trying to understand what their opponents are up to when they play different openings against them, 

I wonder how many people read my post after the first sentence. Apparently not many...

Studying openings can help. Memorizing lines is a waste of time unless you are a pretty strong player to begin with. Many people who are not strong players memorize long variations and those people are idiots.

Wow Paul.  I don't think anyone here could have said it better.  You should seriously consider taking up a coaching job here on Chess.com

Yeah, that cleared things up... *rolls eyes*

For a concrete example, consider the first few moves of a a couple of games I'm playing as black: 1.e4 c5 2.Bc4 e6. When I play 2..e6, it's not so much that I'm thinking that "this is the right move for the opening named sicilian bowdler attack" but that "OK, he wants to pressure that weak f7 with the bishop, so I'll just shut that right down for now with the pawn". You can see the moves themselves are the result of ideas and plans, not just pulled from a catalog. It's just that with only a fixed number of good ideas ideas from white, and only so many counter-ideas from black, you eventually work down to a certain number of basic openings that happen over and over before one of the players gets bored with the whole thing and starts launching some crazy middlegame attack (or at least that's what happens to me :-). This basic set of openings starts to look like a catalog but if you treat it only as a catalog, you forget that it was originally filled with ideas and plans.

Caveat -  I have to say that I certainly don't understand openings very much myself - I only have a half-baked understanding of one as white and one as black, and even with those ones I lose half my games :-)

It's not my intent to clear things up for people who extrapolate a criticism of excessive memorization into an attack and insult on all opening knowledge ever. I don't give a wet slap if they understand or not because they themselves don't seem to make any effort to understand, if they aren't actively trying to misunderstand so that they have someone to argue against. Let them argue and congratulate themselves on being so smart that they recognize study is good and no study is bad. Congratulations!

Yeah, we all know that. I've never heard a single person on this forum advocating that people just memorize opening variations without trying to understand them. But without a certain amount of memorization, it's very hard to play the openings successfully. And studying openings open your eyes to a lot of strategic ideas. The first time a less experienced player runs into Black's 9....Nb8 in the Breyer Defense, it looks like an inexplicable retreat--at least that's how it looked to me--but in trying to figure out what the point could possibly be--redeploy the Knight to d7, open the b-h1 diagonal for the Bishop, free the c-pawn for a possible c5 push--I learned a lot about how the pieces and pawns work together, and how simply "developing" your pieces isn't always the optimal approach. In other words, I didn't just learn one opening variation, I learned a little about chess

Memorising openings is going to give you more wins in 10 minute blitz, because in at least some games it will save you time.

But in blitz you are a lot more likely to easily drop pieces/pawns/the initiative, thus negating anything that occurred in the opening. The longer the game the better quality your moves and the more advantage you'll get from a good opening. 

Time is equally as important in a long game, and you will save the same percentage of time in a long game if you can play out your repertoire quickly.

As a relatively new player...I understand that having a good understanding of opening principles is enough to get you quite far and time is probably better spent looking at mid game strategies and end game technique. Saying that I really enjoy studying and getting to grips with the principles of key openings as it makes me feel like a 'good' chess player and develops my understanding of the game. The opening sets up the mid game and having an understanding of certain openings like say the Queens Gambit..where your pieces are aiming to be and why is really helpful. As for memorising opening lines, it's probably not necessary for lower rating players, especially when your opponents are not going to know the best responses to each move anyway. 

Obviously, in Blitz, and when you opponent is using a standard opening, you are going to save a lot of time if you don't need to "re-invent the wheel" Obviously you won't bother learning openings known to be weak.