I think that it just takes time for people to learn to adapt to new environments, such as newer technologies that work their way into the mainstream. We change our environment, and the new environment changes us. So then you'd be right about the whole thing happening gradually, rather than being some new effect.
At first, for some, they like to create a new identity for themselves, because they can, because it's easy. They're awkward and uncertain about what they're doing, and it can be like another stage of adolescence. But as you develop, you realize how honest you can be. Nobody knows who you are, unless you tell them. Nobody will slap you in the face, 'cause you're not there. People can still laugh at your jokes, but nobody will see you cry. You can be yourself, and no one will know unless you want them to.
Beyond that though, is also our ability to adapt to different forms of communication. At first, the internet can be awkward, because we are lacking the common subtleties of interacting face to face. Gestures, facial expressions, scents, vocal pitches and tones. We lose these things, but we also gain something else. We have font styles and colors and sizes, we have icons/gummis/avatars to represent us, in some cases a better representation of our personalities than the actual face we were given (or so we feel).
Beyond that, I think there are other subtleties that we might only begin to learn about soon. Things that we don't even understand or consciously recognize, but are there nonetheless. I've personally experienced an interesting phenomenon in dealing with people online. For some reason, in cases with people I know, I seem to be able to recognize individuality in things that should be exactly the same.
For instance, a ways back on IMC, I found myself recognizing people based on their gummi, even though they didn't have a custom gummi on their account. The same little blue and black gummi, somehow represented persons to me. Now this is easy, maybe I've picked up subtleties in tags and things that I'm seeing in peripheral vision, but just not noticing. But what's really weird is that I can be on the other side of the room (and mmsword can verify this), and hear an IM ring, and if it's someone I know well, I know exactly who it is, based on the IM ring. I have NO idea how this works.. but somehow it does.
Perhaps there is something to be said about the nature of information, and its transmission; perhaps somehow conscious thought (being tied to electrical impulse) can actually effect the transmission of electronic data, and the human mind is actually capable of picking up these subtle alterations of what would otherwise be identical sets of data. Or perhaps I'm just really freeping weird. (*=D)
Whatever the case is, I'm interested and excited to see how humanity and technology evolve together, and the forms and communication that develop from their intermingling. (^*^)