Macmillan has announced that from 2013 Macmillan dictionaries will only be available online (see this press release) - they will not be producing them as physical books any longer. Macmillan's research has shown that most people get their information via their computer, tablet or smartphone, which explains their decision.
Macmillan Dictionaries editor-in-chief Michael Rundell says in his blog that "The digital platform is the best platform for a dictionary" and "exiting print is a moment of liberation". He also says "But probably the biggest benefit of being online is that the dictionary is always up to date". Well, that would certainly be a good advantage if it were true, but, alas, it isn't. On 9 December 2010 I received a reply from a senior Macmillan employee in reply to a comment I had made saying that the Macmillan Online Dictionary definition for Inland Revenue (namely, "the government organization responsible for collecting taxes in the UK") was out of date. The government organization responsible for collecting taxes in the UK is actually called HM Revenue and Customs (HMRC for short) and has had that name since 2005, when Inland Revenue merged with HM Customs and Excise (as their website confirms). The Macmillan employee thanked me for my comment and said (I'm copying and pasting here) "yes, you're right. We need to update that entry. We should also check any other government department names". Well, they did not update the entry - it's 6 years out of date now - and I doubt that they checked other government department names.