Sign-up.to have done their first pretty large scale report.
It's quite a good read with some very interesting stats.
The fact that the government emails have the best stats cannot really be a surprise and from some angles they might as well be dismissed as many of their emails are so necessary they are almost transactional!
Publishing is one to look out for as primarily that market has been more print related and the digital boom has caused some problems for them. With all of today's free on-line content they have all been trying to find ways to keep the advertisers happy while trying to keep the readers paying too. Some papers have gone completely free - and some of them are now giant adverts with some articles, some have found ways to get paid for content on-line and there is more of that to come. I know Robin Kennedy is up to his eye in paid for content strategy for publishers and it is a great concept but a sensitive one.