Conversate lets you create instant online discussion spaces. It's simpler, faster, more polite, and less annoying than group emails.
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Conversate gives you your own online discussion space for any topic, with anyone you want to invite. It's totally free and ideal for talking about articles or websites and for organizing projects and events.
Has a nice web 2.0 feel to it, RSS for conversations, public, private or limited options, lets you create lists of people for specific topics, and has a bookmarklet so you can just click the tool bar to start a new conversation about a specific web page. I'm very taken with this so far :-)