Peter Kleiweg's dashboard

Add this feature in a way that doesn't change anything for those who don't use the feature. That seems possible to me. The prefix is one option. Perhaps an extra tab on twitter.com that has more options than the 'recent' tab. What about multiple accounts, each with its own privacy setting. At the moment this is not possible if you want to use sms.

At the moment I use twitter for public tweets, and jaiku for updates I only want my friends to read. This is not a good solution. It restricts me in who I can follow, and who can follow me.

This is an interesting idea. It's similar to Pownce's grouping feature, I suppose.

It's hard to say how Twitter could implement this, though. Remember, Twitter is all about simplicity. If there was another field on the tweet form (at Twitter.com), then it would confuse things, and SMS/IM/API users would need an alternative way of setting these permissions on a tweet. There is a possibility Twitter could use the friends and family features just like DMs, but instead of "d" in front of your message, it'd be something like "fr" for friends, or "fa" for family.

Again, though, Twitter tries to be simple, so I personally doubt this'll happen anytime soon.