You must promote, it's a battlefield out there. Soon local supermarkets will mine their own coins, very localized to a country or even a region. Value mostly based on convenience. And I'm waiting for Pokemon Coin by Sony ;p
I didn't say that you should never ever promote anything. 
Just that (IMO) it's better long term if not the coin itself is promoted, but services aroud it (therby a coin too, but indirectly). Assuming that these services will be succesful, offcourse. And making that is really the hard part, and here (+exchange problem,+attracting devs, etc) comes rationale behind coin-focused promotion. With Datacoin there indeed is an added value: secure data storage. I would not know yet what kind of application can use that, but where a possibility exists, applications will be found. I really think they will be micro-small amounts with micro-values (but influenced, in price, by speculation). I think banking, I think personal data like contacts, ... I dunno. Could be subscription based too, leaving datacoin, in value, very static - and stable. With low costs to operate and maintain.
Heh.. I saw something on twitter and I'm thinking about it from yesterday...There are books on more or less free licenses, like CC or GNU GPL. They are, rare. Very rare. But they allow at least for free distribution, or even modification. Thats kind of filosophical value, much better propagated in open-source crowd these days...
If we could finde somebody that wrote a book and made it free as in the speech and is promoting it now? Yeah, I know, with these "artist" mentality happens "once every twenty five years"...
I you're feeling hurt with last sentence look at the quotation-marks!
But if we could, what about publishing it to a blockchain? Ideally with launch of service for that, easy to use for layman (there seems to be krypte already). Sending requires some datacoins. Why not crowdfund that?
Yeah, make buzz, set crowdfunding campain, which goal would be sending free as in a speech and free as in a beer book to decentralized, redundant, globally accessible censorship-free storage.
(There could different cash goals, for sending basic compressed text version, text version+image cover, pdf+epub...)
And if content of this book would fit the above...
YEAH.