Not sure how useful it it, but currently most tags are just simple electronic "post it notes" when dealing with text.
This is a cheap tag which you can push text to like any NFC tags, and then it will auto append it for others to read later.
Reading the guestbook is just a matter of tapping it.
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For a bit extra, you could probably power an electronic paper display to display the last few messages.
This is good for geo tag locations, or local communications. E.g. Next to an art or graffiti location, as a 'guestbook'.-- mofosyne, Sep 10 2014 DIGITAL DEAD DROPS: SECRET COMMUNICATION IN PLAIN SIGHT http://n-o-d-e.net/...munication-in-plainFinally baked as an android app [mofosyne, Mar 25 2016] NFC Message Board Sourcecode https://github.com/...yne/NFCMessageBoardShoddily coded proof of concept essentally [mofosyne, Mar 25 2016] NFC Message Board https://play.google...huu.nfcmessageboardAndroid app [mofosyne, Mar 25 2016] "DIY NFC BBS" https://www.reddit....494yqy/diy_nfc_bbs/photo album by reddit user /u/pseudo_mccoy [mofosyne, Mar 25 2016] This is an excellent idea. What's it about?
More specifically, what's an NFC Guestbook?-- MaxwellBuchanan, Mar 25 2016 (marked-for-tagline)
" Not sure how useful it is "-- normzone, Mar 25 2016 — MaxwellBuchanan, Mar 25 2016
NFC = Near Field Communication
NFC Tag = A small device that can store a small amount of data. e.g. 888bytes.
NFC Guestbook would be to store multiple small twitter sized messages onto such NFC tags from different users.
As for how useful it is? Not exactly useful in most cases. But one person mentioned that he use it as a small "notice" board in various location in some workplace.
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normzone, Mar 25 2016
tagline added-- mofosyne, Mar 25 2016 TIL you're a mod. TIL mods can add taglines. TIL tagline suggestions aren't all being put off for some future date. Or TIL I misunderstood terribly.
Your "digital dead drops" link reminds me of something I saw years ago, which was USB flash drives embedded in brick walls and such with their plugs sticking out, for people to plug their laptops onto to share files. (Of course, there's a significant risk of contracting some kind of infection that way.)-- notexactly, Mar 30 2016 random, halfbakery