Before I saw this reply I already talked about it more here since I saw it needed to be clarified. Now to answer all your questions.

Can you tell us a bit more?

I'll do better I will share the introductory description sent via PM. To give context, a little before this there was an extensive discussion on the pros and cons of various approaches to discovering truth and gaining sanity on mind-killing issues. I think it was in one of the many sub-threads to lukeprogs rational romance article.

I was mostly convinced by arguments against an official mindkiller discussion mailing list, yet I was wondering, would you consider participating in a more informal discussion with a few more people from LessWrong?

A few people that are currently on the list or have been received invitations: [20 or so names]

I've sent similar messages to all of them a few weeks back when starting the list. I am still open to suggestions on who else might be both interested and unlikely to go tribal in their thinking (many people on the previous list where added from suggestions). I'm also open to confidential criticism of the choice for the initial list of people (including myself ).I want to emphasise the usefulness of criticism, since most people so far seem to respond just by adding names not suggesting which should be taken away. As a result the list is a bit bloated.

If you are interested in following or participating please include an email address in your response. Also if you choose to join the group please read the temporary guidelines.

My adress is: [my email address]

Cheers, Konkvistador

Also to again emphasise a key point I fear might be misunderstood I'll quote from the temporary guidelines:

Please don't ever present this or the later the mailing list as anything official or semi-official. It is not. It is just some people from LW talking about stuff.

Now to answer your specific questions.

How many people were on the list?

About 20 to 30.

Was it open or by invitation only?

Invitation only. With people having to agree to new members being added. No proposals where shot down, however people didn't suggest many names.

Was it an existing mailing list or created just for this purpose?

Newly created.

How did you recruit members?

PMs to people on LessWrong with contact info.

Why do you think it failed to be active after the first month

I'm not sure, my best guess was not enough people. Perhaps people where also reluctant to open new topics since privacy protection was pretty much paper thin. My cynical side said it was because the list had too many contrarians who weren't motivated to write because they lacked a non-contrarian audience, and going metacontrarian one more step would require too muhc legwork. :)

Why did you say "as you probably know"?

I thought you where a member of the list. I've now checked, you where invited but you never replied.

I have been on several highly active mailing lists, both open and closed, so my guess is that you failed to recruit enough members.

Most likely explanation.

Why not try to recruit more members?

It has been inactive for some time. Still some discussion did take place, so potentially harmful material may be in the archives, I wouldn't be ok sending new invitations unless the old members agreed.