Martyn Daniels is fond of saying that the publishing business is four different industries linked together by a common format. The Google Frommer's deal shows how far content may now travel beyond the book. If Google's approach to reviews collator Zygat, which it bought a year ago, acts as a pattern, then Frommer's travel information will be subsumed into Google's gigantic search engine and used to provide local (and presumably for travellers non-local) information to users of its social platform Google +. It is likely that revenue will come from advertising, or selling related content. In that scenario the book looks like a distant cousin, three-time removed, and unfashionably dressed in second-hand clothes.

That anyway is the view from Twitter today. Recent figures from BookScan back this. In the UK the sector has shrunk by a third over the past five years due to the rise in online resources – Google Maps, TomToms, smartphones, translators, TripAdvisor, etc, have all combined to replace atlases/maps, phrasebooks and travel guides for some. A market that was once worth more than £100m through bookshops, brought in sales of £70m in 2011, and has fallen by a further 12% in 2012 so far.

Except of course we now know that the book doesn't have to be a book at all to make it useful to consumers. Earlier this year, AA Publishing said it was not planning to commission any new overseas city or country guides, and would not be updating its existing titles, as it wanted to focus more resources on delivering our information across multiple digital platform. Both Lonely Planet and Rough Guides, have community strategies aimed at catering to travellers wherever they are and in bespoke ways unimaginable in a non-digital world. Zagat, itself one year on, continues to publish printed versions of its guides, as well as a £6.99 app that gives access to all of its content for a year.

The history of publishing shows that publishers will sell content in whatever format and through whatever channel it makes sense to do so: Google might not be in the game of selling discrete bytes of content, but it is now in the business of monetising content that it is paying to produce. Welcome to the club. As Google's recent decision to downgrade sites with pirated content shows, it is even starting to understand the membership rules.