we have similar thoughts on Facebook....
Despite lots of our friends being on there and constantly going on about it, it's a method that I struggle with. For instant communication it's great but like you I don't see it as a long term storage for detailed info, either a forum, dedicated website or wiki is the logical place for me. I also don't like typing stuff on a phone or tablet when I have a proper keyboard on a desk !
Having said that, I just logged into the Yahoo site to see what I might be able to contribute to the pot.
Looking at the photograph section, I think that's toast should Yahoo ever decide to delete the data. Too many photos to categorise or download unless there's an option to download a complete album at one click. (haven't seen it, need to look deeper).
The Files section I reckon is saveable. 158mb scattered over 2 or 3 pages of files and as they're in folders it would be easy to replicate that structure on a hard disk if only as a temporary store. I'll make a start on that and see how it goes. I'm not sure how it would translate to a forum format but if we have the data to hand then at least there's options to discuss.
watch this space....
Brian
Update. I've just timed and downloaded the first 10 folders and it's taken under 5 minutes so it's do-able.
Looking through other folders, one thing that does come across is the variety of formats with lots of images just "thrown in a bin" without labelling - ie "IMGxxxx.jpg". It strikes me that if we are to retain the value and be able to find them in future it might be easier to transfer them, along with any accompanying text, into a single PDF file representing that folder.
Anyway I'll download the raw data later today and then we'll have options to discuss.