On Twitter and in Facebook, the default is that you yell into a room and you don’t know whether anyone’s listening. There are friends lists and followers (which is still a creepy term), sure. But the default is to broadcast to everyone; Twitter gets this wrong twice: you’re a freak by restricting your tweets but engaging in public conversations with people who haven’t, and the alternative is to completely dance around the bulk of the system by using direct messages—everyone’s always in the room, and if you want some privacy, you have to whisper.
It has always bothered me that Twitter allows people with private accounts to publicly @reply people with public accounts. This creates a one-way public dialogue, where I can see that my friend replied to someone, but I cannot see the original message (or followups, or context). Frankly, I don’t agree with Twitter allowing private streams at all (if you don’t want people reading your Twitter messages, don’t post messages to Twitter), but at the very least they shouldn’t allow for the mixing of private and public.
The Direct Message system is also awkward due to its mutual follow requirement. Was this system intended to replace short emails? If so, why does it require both users consent to the message (unlike email)? If it was intended to allow users to take public conversation threads private, why does it require both users follow each other when, in most cases, the original poster is not following everyone who replies. While I’m sure the current implementation of DMs cuts down on unwanted messages and spam, it also creates a strange use case: Should I bother checking to see if this person follows me or should I just email them? Do I want to follow this person just so I can send a DM or should I just forget about this?
What Jesper is getting at, in his post, is that Google+’s “circles” allow you to create specific groups of users to whom you can send specific information. Want to share a link with only your frat buddies? Drop them in a circle. Want to start a “hangout” with family only? Invite that circle. Ultimately, I also like this interaction design. When you add on the ability to also post publicly or to specific people directly, Google+ allows for complex but intuitive sharing controls.
(Feel free to add me on Google+. I’ve been posting selectively to the service, but based on my initial use I see a future for it. I’m just not exactly sure what that future looks like yet.)