But some sites have archived at least some of what was on Geocities, so it isn't all lost. One of them is Reocities, which managed to salvage quite a lot. Another is Oocities, though ZoneAlarm flags Oocities as suspicious, I'm not sure why. Oocities has saved several family history sites that were on Geocities, including our own. Of course they will never be updated, but what was there has been preserved. And Reocities has done the same.
And there are some other possibilities for searching for lost web pages and other information: Your Growing Tree- Research Adventures & Thoughts:
I started using Archive.org in my job as a paralegal. It has archived versions of websites that I use in patent citations. The other side of Archive.org is that it archives almost anything...for free. I find live concerts from my favorite band here, and more importantly....books with info for my research. For example- If you look up 'History of Butler County' it brings up several books from the 18-1900's that are searchable and downloadable. These books have had a huge amount of information about the one family that I am researching.
So just when you thought all was lost, something may be found.