Last September I asked if anyone had any data on e-mail usage in government. I got some useful data from friendly sources, and some from a small number of FOI requests. The conclusions are:
1) Few departments have any data beyond how many e-mails they receive and how many they send; they can't break down, for instance, how many come to or from the Internet. Where I didn't get the data from a particular department, I've used the average of the other departments to blend all of the data - not ideal but seemed reasonable.
2) Departmental staff, if the figures are to be believed, receive between 30 and 80 e-mails a month and send about half that number. I'm surprised by those figures - plainly the average hides a lot and there are likely users receiving and sending 10 or 100 times that many.
3) Roughly 60% of all e-mails in government are between users in the same department.
4) About 20% of all e-mails in government are to or from other departments who are on a secure network (such as the GSI, CJX etc)
5) Around 20% of all e-mails are to or from the Internet (e-mails received from the Internet are about twice the number sent though). Remember that government anti-spam and anti-virus (still the same tool we put live back in 2002 or something like that) is good enough to ensure that almost no spam comes through (in 10 years of having a GSI e-mail address, I can't recall a single spam message getting to me)
It's been quite hard to get this small amount of data and I don't think it tells me what I was really wondering - that was whether a case for cloud-based e-mail could be made just from the headline numbers; more digging would be needed to get at e.g. the number of e-mails with "restricted" in the header (which I strongly believe would be ridiculously low, definitely single digit percentage, probably very low single digit) - but I suspect most departments don't have the answer to that (and may claim that because internal e-mails, by definition, go over a secure network, then not everyone labels properly - I would counter that they don't label properly even when they do take the time to label!)