In short:

Tweet Cascade is like a mailing list that runs on Twitter. It allows you to set up a Twitter account that acts like an email listserv, but for Twitter. Isn't that what you've been waiting for your entire life?

That's not very helpful, you say? Then let me explain. No, wait, you don't care about the technical details, so let me sum it up instead...

An actual explanation:

Twitter's communication model facilitates two vastly different types of interactions very well.

Twitter makes it easy to keep up with your close friends. The people who you really are interested in reading when they update you on their cheese adventures. Twitter is great for keeping up with the people in your life for whom triviality really matters to you. When the people you're following are super-important to you, every update is relevant because it's from them.

Twitter also makes it easy to keep up with more traditional-shaped "broadcast" style communication. If you're following an account that's specifically geared to filter for things you care about, then you know that every update will matter to you. Maybe it's breaking news, maybe it's celebrity watching, maybe it's just someone who retweets all the awesome bass fishing news you want to read.

What Twitter doesn't do well is the middle-ground there. Consider our bass-fishing news retweeter. You don't know anything about them other than that they retweet news you care about, and what's more, you don't care to know more. What if you start seeing cheese updates along with that awesome news. You don't care about cheese! Get back to the bass!

Which is to say: Twitter is an all-or-nothing sort of thing*, and that means that talking about your life makes it hard to also participate in conversations with people who don't much care. Tweet Cascade aims to solve that problem using Twitter itself.

Tweet Cascade uses dedicated accounts on Twitter to set up conversational groups focused on specific topics. You might, for instance, set up an account to talk about bass fishing, and to share bass fishing news. Let's call our hypothetical group BassFishingRulez. Tweet Cascade refers to this type of Twitter account as a Cascade account.

You and your awesome bass fishing news buddy follow BassFishingRulez. Whenever you want to say something about bass fishing, all you have to do is start your tweet off with @BassFishingRulez and then Tweet Cascade will have the BassFishingRulez account automatically retweet that message. You don't have to follow any of the individual members, which means you only hear from them if they want to talk about the topic at hand!

A couple of notes:

• In order to keep communities close-knit, Tweet Cascade will only retweet your message if the Cascade account is following you. That is: only members can post.
• Potential added bonus: due to the way that Twitter suppresses messages sent to users you don't follow, if you get involved in a heavy debate on bass fishing, none of your friends who aren't members of the group will be subjected to the furious back and forth.
• Tweet Cascade can also be used for contacting the entire group with a Direct Message. Any DM you send to the Cascade account is automatically re-sent as Direct Messages to all of the group's members. (Twitter already prevents random strangers from DMing you, so you don't have to worry about spammers here, either.
• Once you sign up for Tweet Cascade, you never have to remember that this site exists. All group management is handled via special Direct Messages sent to the Cascade account, so you can use whatever Twitter client you already like! See commands for more details.

Try it out

Sound like something you could use? Check out the join page for more information and to sign up!

*: there's a degree of implicit filtering that Twitter does by suppressing @replies in your feed if they are to people you don't follow, so it's not quite all-or-nothing.