Something called Nurphy has just come out, and it’s an interesting concept that I can see potentially gaining a position for itself. The easiest way to describe it is a cross between email and microblogging (Twitter) and a forum. Effectively you can have a public conversation that can be carried out using a Nurphy account or via email. This conversation, if you’ve set it to public, has a unique URL and can therefore be viewed from anywhere. And if you’ve allowed it, anyone can contribute to the conversation. This would seem to fulfill a conversation need that falls between Twitter and via email. I’ll investigate it for a while.
Here is a conversation I set up to create some screen shots to demonstrate the process.
1. Click the Start a Conversation button

As I hadn’t got any contacts set up at this stage, I typed in an email address and then my comment. You aren’t limited to 140 characters, but equally with this service I don’t think you want to go too big with what you’re writing; it is supposed to be a conversation after all.
2. Your list of Conversations now has that particular one there.

It has been allocated a unique code that with make up its unique URL which can now be publicized.
3. The email address I included in the conversation now receives an email

which upon opening look like:

So for someone who isn’t on Nurphy they are able to participate via email. they receive your comments and can respond by replying to the email and typing beteen the lines delimited by [===> <===].
In this example:

4. From my Nurphy account I can now see the emailed response appear in the conversation:

And I can respond to continue the conversation.

At any time you can use the tabs to see who the participant in a conversation are:

And you have the option of closing off a public conversation to make it exclusive (or private), via the Options tab:

In addition, you can embed some code that provides a button in your site to allow people to start a conversation with you via Nurphy.

If you want to see more of what the potential of Nurphy is, then take a look at the video:
Oh, and there’s an iPhone / iPod Touch interface available.