enable with_friends feature

I think I have that part working. I read on this help post on events that I should request to have my with_friends enabled for the conference user.

http://help.twitter.com/index.php?pg=...

I have submitted a request (I think since I never received a confirmation back).

Do conference attendees only need to be followers? If a conference attendee wants to send a message to the talkdig conference user, will other attendees receive the message? Or does the talkdig user also have to be following each conference attendees?

If your intent is to disseminate your commentary and news about the event, then all you need to do is set up the account and ask people to follow you. There is no need for you to follow people back. Every time you post an update to your Twitter account, people who follow you will receive your update. If people don't follow you, they don't receive anything.

By default, direct messages are only visible to you, the recipient of the message. If you would like to receive direct messages from the people who follow your conference account, then you need to follow them back, because you direct messages can only be sent to you by people you follow. This is where you can send a request to Twitter and ask them to set your account to automatically follow anyone who follows you.

On the other hand, if you'd rather not receive direct messages from anyone, then my suggestion is that you don't follow anyone.

Conference attendees can be passive recipients of your updates if that's all you want them to be. They would only have to be followers.

If you want conference attendees to be active participants who can also post their own updates to the conference account, then there are third party services (such as GroupTweet) that can extend Twitter's basic functionality to support this requirement.