One dimension often missing from these (intro/extro-vert) discussions is the matter of what kind of people and what circumstance the interactions involve.
Put me in a large group of people I have little in common with or with whom I have no interest in -- but am forced to socialize with -- and I'm used up in minutes. But with people I can somewhat identify with, and in a situation which offers something for me, and I can go for hours and leave with equal or higher energy than I started.
There's also the matter of the depth of communication. In larger groups, it's difficult to reach any depth since many people may be involved in the discussion (and many people may behave differently or maintain more defensive walls); but 1:1 or in very small groups it's easier to develop trust quickly and have some very meaningful conversations.
I find many larger group interactions incredibly shallow and boring... just an endless stream of small talk with some attention-seeking, posturing, or peacocking here and there.
I would put that in the introvert spectrum. Complaining about "shallow" interactions is, I think, a big telltale sign of introversion.
I wouldn't call deep conversations a form of socializing, like being alone, this is a bubble, except this time, there are several people in the bubble. Extroverts don't like bubbles, and I am sure deep conversations are draining to them (I am not one, so it is just a guess), and they may want to break free of them, for example, by bringing in other people. On the contrary, in social situations, introverts will want to form the bubble as soon as they can, keeping the small talk and all that to a minimum.
To add to this, I'd say that when people say "deep conversation", they generally mean "comfortable conversation".
A lot of conversations that I've heard described as "deep" are superficial discussions of philosophy/politics (see most of HN) or jargon-filled discussions of specific nerddoms that people are interested in.
Technical discussions are fine, but more personal things are probably what the parent comment is going for. I can totally see an extrovert being annoyed and uncomfortable with the "realness" of conversations that only have place within very small groups.
As an introvert, I would say there is a difference. Deep here is in the eye of the beholder and I agree with idea that a deep conservation doesn't drain me and can in fact be energizing. Comfortable conversations are more on the fun and light sight but they can be an drain on my limited social energy reserves. I like them, but I need recovery time. The 'deep' part may mean different things to different people but to me its one where knowledgeable people are discussing aspects of that knowledge at a, well, deeper level than most conservations allow for.
That's because introversion/extroversion is really only one single axis. The Big 5 personality index includes 4 other axes: agreeableness, openness, conscientiousness, and neuroticism.
What you're discussing is only partially described by extroversion. Highly agreeable extroverts may not enjoy large group discussions because of the inherent conflict present when multiple people express opinions. Highly conscientious and low opennness introverts may not even like 1:1 discussions because they're so very sure that their existing opinions are the correct ones.
Humans are really bad at multi-axis categorization. We like things to be good/evil, black/white, etc. But anything worth categorizing almost certainly needs to be categorized across multiple indices.
To add to that, if I need to support the conversation moat of the time and feel like it's work just keeping it flowing because the other person just doesn't have an interest in me or what I'm saying, that drains me.
Put me in a large group of people I have little in common with or with whom I have no interest in -- but am forced to socialize with -- and I'm used up in minutes. But with people I can somewhat identify with, and in a situation which offers something for me, and I can go for hours and leave with equal or higher energy than I started.
There's also the matter of the depth of communication. In larger groups, it's difficult to reach any depth since many people may be involved in the discussion (and many people may behave differently or maintain more defensive walls); but 1:1 or in very small groups it's easier to develop trust quickly and have some very meaningful conversations.
I find many larger group interactions incredibly shallow and boring... just an endless stream of small talk with some attention-seeking, posturing, or peacocking here and there.