Thanks for the note on progress, I have little knowledge that would be helpful.
I can report that the NMUG (Norwich Mac User Group) went to Groups.io some 6 months ago, and everything is fine so far. I am in the UK.
I've been reviewing the options, and I think the two best options would be WordPress wikiWP, or to host and create a custom made wiki using MediaWiki. Google Sites, PBWIki, group.Io, and EditMe all have major drawbacks. Google doesn't allow direct import of html with its new format. Group.io isn't will suited for the needs of the wiki. PBWIki and EditMe would have much higher support cost.
I am more partial to a cheap or free web server with apache, php, and mysql support. With a self created MediaWiki site, you will only have to recreate the site once, and will never be dependant on having to migrate to a proprietary format like now.
I see this as less work than the WordPress migration, and again frees the site to move as need and retain format.
I migrated from TMG to RM7 and I am still cleaning up data that did not transfer correctly. Looking at Wikispaces generated pages there are many proprietary functions and the code is very specific and not relative. Every link points to a fully resolved URL and would need to be changed many times for each page that you have. Also there are many resources that are part of wikispaces that would need to be recreated for use once wikispaces goes away. I can give more specific examples if needed. It looks like you would need a large manual effort to recreate what you have already created. (I tried copying two pages to see what the effort would be to convert to relative addressing and it would be as time consuming as the manual effort)
If you define the functions that you need they would be:
Create an account for a user with login and logout features similar to what you have.
Provide for user input for their suggestions on SQL for Rootsmagic.
Have an easily navigable structure similar to wikispaces.
Migratable code in case your next effort results in the same problem as wikispaces
Provide for rock solid solutions that a user cannot edit. A user would submit, possibly visible to the public, and the suggestion or code would be verified by you or a support group and when it is ok, moved to the general layout of your site.
I have copied/stolen/appropriated some of the content from your site to preserve it for my own use should something happen to your migration plans. I have created a spreadsheet of your database structure and a graphic of the database of my own showing how the tables all relate and which fields that are used to link the tables together. This is not complete yet. I was able to generate very simple code to display the spreadsheet and the spreadsheet itself was created using Excel and saved as an html file. This simple code could be transferred intact to many many hosting sites as it is just plain vanilla code therefore protecting your next effort from changes like what you are seeing now.
I have had some programming experience so I would opt for something like this:
A webpage(s) that would be static and be only updateable by a select few. A hosting site that could be as cheap as $4 per month. No logon or databases required as it would be viewable by anyone.
I would probably create a facebook page that would allow for public input and comments and discussion and posting here would be caveat emptor and your group would move the suggestions/code from the facebook pages into your static site.
The facebook page and the static website could be linked together so it presents a single consistent interface.
Just my 2c on this issue, with no in-depth experience on any of the other solutions mentioned, but then I don't always chose the easiest options.
I've tried a migration to mediawiki, and I agree with Ed that it's gong to be more time consuming and prone to errors to migrate as opposed to recreating the site from scratch. I took five pages and tried the migration, and recreating the pages from scratch, using copy and paste directly to the wiki site on the usb stick. It was quicker and cleaner then trying to find and fix broken links.
I like to concept of a wiki much more then a static web page, but feel keeping the site in a format that that isn't priority is important as well. MediaWiki is the best solution if you want to maintain a wiki. Next best option would be a static webpage with a separate forum. I think this would require more work in the long term to maintain than the wiki. Either option will require php, sql, and apache on the server to operate fully.
What is the size of the whole wiki now Tom? If it's small, I remember there were a few free servers they had these built in.
Was "priority" autocorrect for a mis-typed "proprietary"? Yes, in response to both yours and Ed's points, I am concerned about the transferability of content. Wikispaces, to its credit, is pretty good about it. If you are following my Wikispaces Refugees group at https://wikispaces-refugees.groups.io/g/main, you will see the export options listed.
MediaWiki is one of the formats and I could send you the 70 MB ZIP file (PM me with coords). One of the alternative sites suggested by Wikispaces is Referata.com which uses MediaWiki but I discovered it wants the page in XML format, not any of the formats exported by Wikispaces.
Tom, I need access to the pure XML dump... Can you give me access or post it on google drive?
There is no dump in which the pages are exported in XML. I think all of the exports except PDF include a XML file of page Discussions and Comments.
Thanks to cooperating providers, I have multiple trials going for migrations of this site. I hope to get around to making some comparisons and observations but you can look at them yourself and make your own. They are all listed in the Wikispaces-Refugees Databases table "Wikispaces Migration Examples" at https://wikispaces-refugees.groups.io/g/main/table?id=4607&q=%22sqlite+tools%22
Trials hosted by EditMe and CiviHosting have ended - they both gave me more than 30 days but would not do so until September. I am occasionally futzing around with free hosting for HTML, DokuWiki and WordPress. Page Comments and Discussions are still the biggest hurdle but there are numerous other issues; the former may simply have to be copied into their page. EditMe did the most complete and easiest import but their hosting fee structure is too limiting and costly. Groups.io is still so Yahoo Groups import focussed and email reflector oriented that I cannot see it working except either with an external host for images and other files or as a discussion group loosely linked to the main website. I'm not satisfied by anything yet so, ultimately, the best of poor alternatives will be what I go with. Basic HTML for a non-discussion website is easiest... WordPress is prettiest...