Has it ever occurred to you that we've managed to set up our information channels exactly the wrong way round? The majority of telephones, for example, are still linked to the telecommunications network via fixed cables in homes and offices, despite the fact that they'd be far more useful if they were all mobile. Whereas televisions, which hardly ever move, are in theory far more portable because they receive their information over the airwaves.

The fact that phone numbers are in a fixed geographical location, however, inevitably leads to privacy issues. You may remember a couple of years ago when a German company announced that it was going to publish the entire UK phone book on a CD-rom. The difference was that this system would allow people to look up addresses if they only knew the phone numbers - a so-called reverse search.

It never happened in the end but there are limited alternatives. Brainstorm, for example, will give the geographical location of every area code in Britain. This isn't all that spectacular, of course; British Telecom publishes an area code handbook with similar information. But there are more sophisticated versions of the same thing. Multimap lets you type in a phone code and it will throw up a map of the relevant area. The site also supplies website addresses for places in the area. Whether you think this amounts to an invasion of privacy, I'll leave you to decide. It does seem to be moving into a grey area. Especially in built-up urban areas, for example, your car numberplate and your phone number would be enough for anybody to establish where you live.

Before you get too upset about this, you should remember that in the US, reverse searches on the Internet are theoretically easy, and I've yet to meet an American who has any strong feelings about it, perhaps because Americans have much healthier ideas than we do about freedom of information. But it does highlight one of the advantages of email addresses; the fact that your address never betrays your (domestic) location.

One of the biggest search engines, Sales Leads USA, claims to be able to locate the phone numbers of specific individuals as well as carry out reverse searches, although when I tried it with three people I knew in America, it didn't manage to find any of them, which suggests that it can't be all that comprehensive.

On a less serious note, you may also remember that with old fashioned dial phones, there used to be letters associated with each number on the dial; 2 corresponded with A, B and C, 3 with D, E and F, and so on. Dial ABC will let you find mnemonics to help you remember phone numbers more easily. Again, it's something that the Americans go for in a bigger way than we do, and there isn't a privacy issue involved, although there is always the potential to be embarrassed if your number turns out to spell something incredibly rude.


Locations behind UK and international dialling codes


UK maps by area code


Sales Leads USA. Can also look for addresses through phone numbers


Mnemonic devices to help you remember numbers