Since I've had a LiveJournal since the beginning of the decade, I obviously don't have a problem with putting my thoughts online for others to read and comment on, and it's a fun way to meet and interact with others. Heck, I met my wife barlow_girl here, so I'd be among the first to recognize how great a platform this can be for getting to know people. But part of appreciating LJ and online interaction is knowing what I believe their limits are.
Without conscious effort, it's easy for me to believe and act as if other people are accountable to me for what they write online, or worse yet, that they're here for my entertainment. When I step back and think about it, I know those are rotten beliefs that are still more rotten for me to act upon, but for me they creep in really quickly and easily—it's such a narcissistic way for me to relate to others. So even though that's not completely unavoidable, I'm still wary.
Along those lines, I think it's also easy both to act like and to see others online as caricatures of who we really are. Not only do we only bring certain parts of ourselves to the virtual table, but we also fill in lots of the blank spaces in one another's attitudes and motivations with our own stuff (and let's be honest—lots of that stuff is crappy). Heck, we even overwrite their stuff with our own. This can create a minefield of unnecessary misundertsandings.
Lastly (at least, lastly in what I can think of right now), there are problems of speed and magnitude. Alongside the inordinate opportunities to really miss one another, things move quickly when I'm processing them here. As a result, not only can I misunderstand someone instantly, but I can also pile on huge loads of other stuff in record time, often long before I realize that I've missed the relational boat in the first place. It's not fair to others to bury them in my stuff, and while that's a necessary risk in any relationship, the internet as a medium turns those risks way, way up—more than I believe is good much of the time.
The bottom line is that relationships aren't intended to be nearly as much about me as they can seem to be here. Other people's stories are just that, and the more I bury them in my own stuff, the more I feed the beast of my own ego. Others don't need to entertain me. They don't need to agree with me. They don't need to play by my rules. And of course, of course I'm going to have responses to our differences, but most of the time I need to either work those out on my own (my journal is still mine, however) or with them (somewhere other than the internet).