Anonymity is a part of privacy. The ability to speak your mind or do your shopping without some organisation filing all your actions away is an important part of natural freedom. Expressing opinions corresponds closely to casting a secret vote.
You normally have some people by whom you are happy to be recognised, and some you aren't. E.g. you may be recognised individually by a number of shopkeepers, in shops where you pay with cash. If you paid it all by credit card the card company would have ready access to details of your shopping habits. The differences lie in the collection of your details into one place, and the fact that the shopkeepers may help you by knowing what you usually want. Built into the central Big Brother data gathering mentality is the idea of recognising the same person as the same in all circumstances. There is no need for the many shopkeepers who know you by sight to have your name, or for them all to know you by the same name. Ever noticed how the Good Samaritan's name is not recorded, and how he paid in cash ? (Luke chapter 10)
Everybody agrees that anonymity can be abused - for instance by people making nuisance calls from public phone boxes, or sending unpleasant mail without including their name and address. There are longstanding methods for dealing with this sort of misbehaviour, without prohibiting the services in question.
Electronic aids to anonymity include anonymous proxies of various sorts. Theses are devices you call that undertake some task for you, but without disclosing your identity. A well-known example is the remailer network. Anonymisers for other services are also available or planned.
There are no remailers operated at notatla.org.uk.