Is groups.io free?

Yes. It is free for members, and it is free for a group on the Basic plan. It is not free to use the Groups.io Transfer Agent - see #2.
Pricing and features: https://groups.io/static/pricing

How do I move my Group to Groups.io?

Note: there is a short time left before YG's message archive is deleted.

(a) Moving members yourself:

  • On the Basic plan (free) you can upload a list of members to the Invite page. Similar to a Yahoo Group, it sends an invitation to each email address and the invitee must receive and respond to the invitation before they are added to the Members list.

Details: https://groups.io/g/GroupManagersForum/wiki/Inviting-new-members

  • You can Upgrade your group to the Premium for one month plan ($20 USD) in order to upload a list of members (Direct Add). However everything else would need to be copied manually.

Details :Direct Add members

  • To obtain a list of your Yahoo Group members you can go to the Manage Members page and in the Actions menu Export (download) a csv or tsv format file. It is best to open the file in a spreadsheet like Excel, then you can easily copy the Email column to paste into the Direct Add or Invite page. Note: this is only for groups with 1000 or fewer members, due to Yahoo's Export restriction.

  • Send a message to your YahooGroups members on YahooGroups inviting them to join your new home. Include the URL. Or tell them to send a blank email to the Subscribe email address found at the bottom of your group's home page (that is, [GROUPNAME]+subscribe@groups.io  substituting the real group name for GROUPNAME). Since you won't be using a G.io invitation, you may have trouble tracking members who don't respond. 

(b) Moving message archive, photos, etc. yourself:

There are two parts to this - downloading content from your old group and uploading to your new group in Groups.io

Downloading:

There is only a short window at this point for downloading from Yahoo. A matter of days.

How to download content from Yahoo - see https://groups.io/g/GroupManagersForum/message/19430 

There are a few third-party solutions to do that, including PG OFFLINE, and a Chrome browser plugin

Uploading to Groups.io

Here's an overview:

https://groups.io/g/GroupManagersForum/message/25789

The problem is what to do with the message archive once downloaded; as there is really no good way to re-upload it to groups.io, to re-link individual messages to their owners, or to provide online message search capability.  It's not the same as a transfer and loses "ownership", but Lena has a way to get the messages into the archive, https://groups.io/g/GroupManagersForum/message/22251 

 

(PG Offline is a Windows program. You could set up a Windows emulator on your Apple computer.)

 

An option is simply to print the collection of old messages to a PDF file; at which point you can upload that to the files area of your group. That will give you something, even if it isn't conveniently indexed and searchable.

It is possible the Groups.io may be able to move MBOX files in. (Been mused about. Not a sure thing.) But see (3) above and #14. 

Archive Team is backing up the entire Yahoo Groups on https://tracker.archiveteam.org/yahoogroups/ This group has a few thousand computers activated as a massive effort to retrieve and archive all of YG.  No matter how big or small the group may be.  As for private groups, they do 1 of 2 things, 1) request membership and then archive or 2)  ask from their site for owners and mods to send an invite to the group.  See https://www.archiveteam.org/index.php?title=Current_Projects

Currently  (Nov 2019), the only way to have the correct ownership for files is to have the owner upload it.

Moving messages to Groups.io in mbox format

If you can obtain the group's messages in mbox format, Groups.io can import them into your Groups.io group. For this, you must pre-pay for a year of premium service for your Groups.io group. Contact support if/when you're ready to go ahead with that. Note that the mbox import includes only the group's messages, you will still need to copy the group's members list, photos, files, and other content by alternate means (see above).

Yahoo Groups: You can obtain your Yahoo Group's messages in mbox format by requesting a download from Yahoo's getmydata function. To do this you must sign in to Yahoo as at least a member of the group in question. Yahoo will ask you to re-confirm your sign-in credentials each time you visit this page (first to request the download, then to download it when ready): https://groups.yahoo.com/neo/getmydata You will be given a link to one or more zip files to download, the mbox files for your group's messages will be nested within (one of) those zip files. You must request the download before December 14 in order for your request to be honored.

(c) Photos and files:

You'd need to move them manually if you're not paying for a transfer.  It can be time consuming and "ownership" of all the items will be in your name.  If the person that originally uploaded a picture is on the new group, you can manually assign ownership to them (if you know who it was.)  

There's currently not a similar function for Files.

Where can I find out about starting my group and setting it up?

https://groups.io/g/GroupManagersForum/wiki/Quick-Start-for-Group-Formation

Where can I find instructions for joining a group?

https://groups.io/g/GroupManagersForum/wiki/Joining-a-group

The official Groups.io user documentation is in the Groups.io Help Center.