I think people are generally more comfortable being who they are online. It acts as a safe space to learn who you are and express aspects of their personality, because if you're being insulted or criticized for an aspect of your interests or personality, you can remove yourself from that much more easily than you can in meatspace. Anonymity also doesn't expose you to as many long-term repercussions for your actions. However, that ability to shelter yourself from unpleasant things, such as legitimate but unpleasant criticism, can also make you less likely to seek to change or improve, and less beholden to externally-imposed responsibility (such as from laws or social mores), which as a result can inhibit your personal growth, and the development of deeper levels of personality.
To bring this back to the topic at hand, one of my most fulfilling relationships started with someone I first met online. We used the neutral space of the internet to get to know one another on a pretty deep level over the years, and visited whenever we could. Though it didn't work out in the long term, it was really nice to have had, and we stayed good friends afterward as well. Still, you definitely learn a lot more of the nuances behind people once you've been with them full-time, rather than in little spurts of communication... be it through phone calls, chat programs, letters, or what have you.
Yeah, I'm a huge supporter of character being "who you are in the dark." The mask of anonymity shows people as they really are, online.
I feel it's more that we are all our masks. The one you wear in the dark is just the mask you wear so you don't have to face yourself.
I think there's some truth to that. Personality is a thing we build for ourselves over time, both consciously and unconsciously. Our personalities are anchored around quirks and traits we've identified in ourselves, codes of conduct we opt into, and tags we label ourselves with, like Football Fan, History Buff, Birdwatcher, etc. I don't know if there is ultimately a "True" self underneath these masks we build up around ourselves, so much as a really basic and fundamental mask we use to anchor and guide ourselves... and when that gets challenged, we feel lost until we find or create a new one to provide us with direction.