In the last episode of N'Gai Croal's adventures in social networking, I was just a few months into Facebook and expressing my unease about friend-tracking services like Spokeo. For me, Facebook's most persistently compelling feature has been the status updates: I fill in the blank for "N'Gai is ___" with the message of my choice (e.g., "grinding," "working for the weekend," "fiending for Tartine," my favorite bakery), and presto! All my buddies are notified of my current state of mind. During my early days on the service, the thrill of status updates was primarily voyeuristic, as I chose to read other people's status updates rather than pen my own. But once I dipped my toe into the water and discovered the narcissistic pleasures of thoughtcasting, I was hooked—and even more so once I downloaded the Facebook mobile application to my BlackBerry. Now, whether at a computer or on the go, I could share snippets of my riveting, elegant prose with 800 of my closest friends, 24 hours a day. Which I then proceeded to do.

The question I've been asking myself lately is this: just because I can publish my every thought, does it mean that I should? What prompted this reflection wasn't Facebook but two newer services, Twitter and Tumblr, which take thoughtcasting to another level. Twitter is much like the Facebook status update: you answer the question "What are you doing?" in 140 characters or less, and your response is sent to your friends via mobile phone, IM or at the Web site. I started out using Twitter to promote new posts on Level Up, my NEWSWEEK blog about videogames, so that I could reach out to interested readers beyond Facebook. But once I connected Twitter to Facebook so that all my "tweet" messages would also show up on Facebook as status updates, that was all I needed to make the switch. I even started using the service as a way to publish live updates from events and conferences. (Sample tweet: "Nintendo's Cammie Dunaway makes 'rewind' sound effect during presentation. [Beatbox artist] Rahzel would be pleased.") For more of this chatter, see twitter.com/ncroal.

Where Twitter focuses on text and links, Tumblr lets you express yourself using multiple media—photos, audio files and video clips—but in a manner that's infinitely easier than traditional blog software. I started messing around with Tumblr halfway through the Saturday of Memorial Day weekend, and by Monday, I'd created four new blogs without breaking a sweat (check out two of them at ncroal.tumblr.com and page110.tumblr.com). This brings me back to my dilemma: by cleverly and radically reducing the barriers between private thought and public expression, Twitter and Tumblr make it so easy for me to publish whatever is on my mind that they started to seduce me into actually doing so.

I asked Twitter co-founder Biz Stone, 34, and Tumblr creator David Karp, 22, how they distinguish between what to publish and what to keep private. "If I feel like being alone, for example, I won't share my specific location when I update," Stone says. "If something is somewhat private but I still feel like updating Twitter, then I'll leave out specifics such as names." Karp says that his Tumblr page, David's Log (davids log.com), has become his online identity. "That's where everyone I care about follows me," he says. "While I do share personal stuff, it's not as raw as some." I posed the same question to my 551 followers on Twitter, which elicited such responses as "Things I would talk about on my blog," "Anything I can be seen to be doing in public," "Things that wouldn't disqualify me from running for public office," "The Mom test ... would I want my mom seeing it or not" and "common sense." I'm still figuring out this thoughtcasting stuff, but Mom and common sense sound like a good place to start.

© 2008