I’m organizing an conference for about 300 people at work. The conference is mostly about networking. Now, my (government) organization is still living in the Stone Age of ITC, and their idea of facilitating the networking is giving out a (printed or digital) Excel sheet with names numbers and adresses.
I have been toying a bit with networking sites like Plaxo and Linked in and I get the impression they are the modern standards for professional networking.
My question is, is there any way I can use these sites for my conference, other then telling every one “If you don’t have a Linked’in account yet, bloody get one, you dinosaur?” 
For instance, can I set up a group (“Attendees to The March Very Useful Conference”) and enlist members?
Thanks in advance for any pointers.
If you have a list of attendees’ email addresses in advance of the conference you could send, via LinkedIn, an invitation to join (I am on LinkeIn but not familiar with Plaxo). You could set up the group you suggest though I think they would have to be on LinkedIn first, and you can invite them to a group but you can’t just make them a member of the group, AFAIK.
Thanks! Could you perhaps also tell me what advantages a group on Linked in has, when compared to an e-mail distribution list, for example a list created to send the people on it a regular e-mail newsletter?
When you update any information about yourself, it can automatically be sent to your contacts (like if you change jobs). There is static information (your profile) that is available to your contacts anytime they want to go look. You can look up people you are connected with, and see who they are connected with. The site automitically notifies you of new connections that your own connections make as well. You can post job recommendations for other people, which can then be seen by anybody checking out that person’s profile. I have 67 contacts, but those contacts have a total of over 9,200 contacts. The scope of your sphere of influence ramps up pretty quick.
Using mailing lists is OK for some things but much more limited. The only way to communicate to people on a mailing list is to proactively send an email. The information sent might be saved by the list service (like Yahoo! Groups) but it’s still just a pile of emails with no organization. In a networking site like LinkedIn, there are lots and lots of members, any people can find you and contact you. You can’t do that with a mailing list unless you know* a priori* that the list exists and who to contact about it. As you noted yourself, you can establish a group within the site for special interest communication.