As some of you will have seen, and as we announced recently, we have started to put email usage in to one of three tiers. They are Light, Standard and High.
The tiers are based on number of emails processed (including spam) so are a reflection not just of how much email you get but how much you put your email address about (e.g. on forum, web pages, news groups, etc). This is also affected by how many aliases you have or whether you have a wildcard alias. Emails to invalid addresses do not count.
We sent out emails this month to people who were not on the Light level of usage. The emails were not worded very well, for which I do apologise. I think you will find the ones sent next month to be a lot clearer.
We are only changing people off a lower tariff to a higher one if you have high usage for three months in a row. Even then the price change does not come in until the next bill. So this is lots of warning.
Are we trying to rip off customers? Of course not! Email is however an expensive business to run, and as you can see by the slow down last week it is not easy to keep on top of it. We had already ordered a new, and very fast, storage server which we hope to install this week. We have a lot of machines doing email (incoming, spam checking, webmail, imap & pop, outgoing all have at least 2 machines). This is more equipment, power, bandwidth, and rack space than any other service - yet for over half of the domains we run we include email free of charge with the broadband and the rest only cost £1/month.
We are keen to include a domain, email and web space with broadband still, but it is not sensible for someone to use the free domain to handle 250,000 emails a month for a company with hundreds of mailboxes and "pay" the same as someone that has a home email address and 100 emails a month, is it?
90% of domains on which we run email are in the Light category which is free with broadband (one domain per site) or £1/month+VAT. A cheap service.
For 9% of domains we handle over 1,000 emails a month and and this is the Standard email service. It is only £5/month even if you have broadband, which is not an expensive email service. Remember it is still unlimited mailboxes.
For 1% of domains we handle over 10,000 emails a month, and these are an handful of companies using our email with, typically, hundreds of staff mailboxes. These will be charged £100/month.
The exact proprtions will change, I am sure, as some people will take email elsewhere and some will stop wildcard mailboxes and so on.
We expect this change will either provide more money to help maintain and run a good quality of service, or move some of the high users again making the service better.
I hope that makes sense, but do feel free to ask me questions in irc. | 
