Hi G...,
I was thinking of you earlier today, ....
... your questions about pres. storage and retrieval sites, and identifying copyright material in extant presentations, might be a bit wide of the PSG's self-circumscribed remit. You still might [want to] inquire of JALT CALL SIG folk. Nevertheless, here's my two-cents['] worth.
You're right about LinkedIn's appeal outside academic circles. I opted for SlideShare years ago, for ease of use as I recall–probably before integration with LinkedIn. However, I've been unable to find any spec's for free storage space today. Once you've uploaded to Slideshare (PDFs were recommended), content becomes virtually static, i.e., un-collabor-able. That is, unless you consider deep-diving (threaded) discussions [in comments] collaborative, which they may well become in certain other venues. I don't recall ever encountering or engaging in discussions like that on Slideshare.
Regarding possibly copyright or otherwise licensed material in ready-made presentations, if it's images you're concerned about, Google (or other) image searches might turn up original sources and contextual authorship/licensing details. On blogs or other websites, I've found, those details usually appear on top pages and in page footers.
YouTube once unceremoniously removed sound from a video I'd mixed with a tune that had come pre-packaged in the Mac video software that I'd used to produce it. Rather than attempt to argue (or litigate) the point against YouTube's done-deal, I simply replaced the tune with similar licks from a free music source. [A similar tactic may serve for image or text mash-ups.]
Searches for text snippets you'd like to retrieve and acknowledge [the]... sources for might turn up periodicals (behind paywalls) or books (with sample pages visible on Amazon) as well. Covers and copyright pages of books (or previous citations with publication details) may be visible in or accessible via search results. Newsy articles may no longer be accessible at original URLS, if at all.
Rediscovering exact page numbers for reference citations can be time-consuming if not troublesome. Requesting full texts of periodical articles from authors (via Academia or ResearchGate) or sending inquiries to journal editors are options. Both such sources may be keen on planned or projected citations.
The best advice I can offer is forward-looking; collect all the details you think you may need–and more, when you first encounter suitable source material.
If you do find primers covering those sorts of intellectual property rights re-discovery [emphasis added], please point them out to me! I'll be happy to add them to the PSG's Diigo Group bookmarks.
Warm regards,
PB
Paul A. Beaufait
Owner/Curator/Admin.
