As it turns out it was very wise decision to move away from YahooGroups in the light of current announcement of shutting down the service on December 2019.
I have taken steps to download and preserve content from YahooGroups, but anyway if you have something that you want to keep from old YahooGroup, make sure to store it locally.
Long live Discourse 
If anyone is interested in downloading all the Yahoo group contents and saving locally, some time ago I found this cheap shareware software:
http://www.personalgroupware.com/pgoffline-index.htm
It is slow and far from perfect but you can decide if it is worth after a free trial.
The archivist team @ archive.org is also hard at work getting everything archived. All public groups are being archived, so you'll be able to get it there soon as well. I don't believe they've started adding things to the main site, but they may have.
Does anyone have the yahoo groups content available in PG Offline .mdb format please?
If you are member of YahooGroup you can download the archive from Yahoo, but if you are not, then due to privacy laws (emails and names stored in such archive) I strongly urge NOT to use this forum for exchange of private sensitive data.
Hi Tomasz, I am a member of the Yahoo group but I don't see any messages there to download.
I must have that PG database somewhere.
If you are subscriber to YahooGroups you can export https://groups.yahoo.com/neo/getmydata
For those who missed the yahoo group download deadline, is the content somehow available? Has anyone made a backup and ready to share for download?
For privacy reasons we can not provide content of YahooGroups to the public. Only people who were members could download the archive directly from Yahoo and only for their personal use. Any distribution of that data beyond that is a violation of GDPR law.