Amazon's purchase of The Book Depository reminds us that, despite the huge growth in e-books, the world's largest retailer has not taken its eye off the ball when it comes to the physical book market. To the disappointment of some.

The Book Depository has for a long time been something of an unsung hero in the UK bookselling market, growing to sales of perhaps £100m incredibly quickly at at time when the other booksellers have flat-lined. It has achieved it by focusing very clearly on one message--books delivered free "worldwide"--and steadily expanding those parts of the world where that message applies. The company now ships free to more than 100 countries, with overseas sales making up about two-thirds of the overall business.

It is big in those areas where Amazon isn't, and in Australia competes head-on, with some success. Most importantly, it has established networks and routes into those countries, which Amazon simply does not. And I suspect it is these, rather than the turnover, that Amazon is most interested in.

An inquiry by the Office of Fair Trading seems inevitable even though TBD's UK sales, between £20m and £30m, seem in themselves unlikely to take Amazon over any threshold it isn't already well over. Pearson, which has acquired the online business of REDgroup, ostensibly to keep this distribution platform alive, might be feeling doubly justified following the news. The combination of Amazon and TBD might actually have a claim to be Australia's biggest bookseller: and one with no presence in the country.

For those who appreciate diversity the acquisition is unquestionably bad news. The Book Depository's twitter feed is already alive with customers rallying against the move. As one of the more polite tweets suggested: "Anyone interested in banding together to place a counter-bid against. I've got $60." Another customer simply commented that he used TBD because it wasn't Amazon.

It is hard to imagine that TBD's culture won't be diminished by being consumed by the taciturn giant. Already calls to The Book Depository founder Andrew Crawford and m.d. Kieron Smith are being re-directed to Amazon's PR team: though team seems a grand word for two people nick-named, by former colleagues at Publishing News, "no" and "comment". One brief press statement is an odd way to communicate such news to customers and suppliers, but it is the Amazon way. Some tweets have escaped with the company saying that it will "continue to operate independently". The tweet is now being repeated Ed Miliband style to individual customer questions.

None of this means that the TBD isn't the right fit for Amazon. In fact it looks like a very clever strategic move, from a company that has barely put a foot wrong in over a decade. And Amazon does own and run other businesses - LoveFilm to name one - without destroying their personalities.