Here are some of the pros and cons of Google Groups vs Yahoo Groups. Please revise and update if you have more information.

 (Summary table at the end of this page.)

1) In Google Grups you can have members self-enroll or you can invite members. However, totally free self-enrollment invites bots and spammers. Inviting members means you have to receive an email request individually and then go to the Google site to add the new member yourself--and respond to requests quickly. (Remember, you are looking at 50-100 requests in the first 2 weeks.) In Yahoo, you approve members who attempt to self-join, but you can approve a whole batch of requests daily from one place without clogging your email box. You can ensure that potential members write you something to indicate they are human. So in YG we can quickly find spammers and boot them out and they can't rejoin immediately, as they could with Google  groups.

2) In YG, you can send out an automated welcome message when people join that can be fairly complex (not just 250 characters as in GG). This could include the syllabus, PWs, and site links for a wiki or other resource venue. In GG you'd have to send out emails with this info, or post that info on a page that might lead to potential spam of other linked sites.

3) In the first weeks of a session, there are usually email and PW problems. In YG, we can trace "bounced" emails and help participants with their mail settings. I don't see those features in Google, which is more open-ended. New members may get lost.

4) GG delivers mail, I think, as individual messages when a forum you are following is changed or has comments (anyone know for sure on this?). That could wind up flooding some mailboxes. Participants would then probably have to go to the GG site to view mail, which we haven't found to work particularly well for a vibrant conversation in a short time period. YG delivers mail in Daily Digest or as individual letters, or by viewing the website.

5) Google groups is organized, like Moodle, into forums or discussions, each separate from the others. Any participant can start a new, separate discussion thread or sub-group. Over the years in EVO we have found that having one uniform elist, as in YG, is far better for building community and cross-seeding discussions in the short time allowed for our sessions. One of the coordinators who has used GG extensively said the threaded email discussions are very confusing, and she had become very discouraged in using GG.In 6 weeks there isn't much time to split off into separate discussions, but Yahoo messages can be "threaded," in effect, by searching for a topic or key words, which produces a list of all messages containing the words as well as subjects/topics. If you want your session to be divided into independent teams or discussions on unrelated topics, you might want to use Google Groups for this purpose.

6) When you look at the frontpage of a GG, it gives you a list of discussions, pages, members, and files (to downloaded). This is not as welcoming and informative as the YG frontpage, which can be edited with html, and include your logo, information about moderators, calendar, links to sites not inside the group, etc.

7) At this point in EVO we use the YG mainly for our elist discussion, while the wiki is for other stuff.  GG has the  wiki-like "create a page" function, which could be used to store links to resources and tools. So GG might replace a wiki. However, the real wikis are now allowing some pages to be locked so that only moderators can change them. I don't know if GG has reached that point yet, and it certainly not (yet) a full featured wiki. On the wiki-style pages of GG, I found you really can't make tables, which are incredibly useful, so this limits its functions as a wiki. Someone in a user group suggested that you could make a css page to use in GG, so there may be work-arounds for this limitation.

8) Another reason we have used YG in the past is that the Yahoo ID is the same as for Messenger, which we use as a back channel for chats, so this means the participants need only one ID to remember. Of course we now use many different venues, and participants usually are more used to handling IDs and PWs for multiple sites.

 Here is the address of a Google Tour. For more info on using Yahoo Groups, check the sidebar for wepages created specifically for issues in EVO.