Here is an edited version of the email I wrote to my father. The email finishes with an exploration of the real problem, which is that my father feels disappointed that the Internet in theory provides a mechanism through which he might track down and contact some of the people he knew as a young adult but it doesn't work as well as hoped in practice. If anyone has any ideas, please let me know.
The company that listed the names of our family alongside those of our neighbours is called 192.com. They appear to have combined the 2002 electoral role with the 2009 electoral role. 192.com market themselves as a people finder and a directory enquiry service. The positive side of their services is that people or companies can check the bona fides of, say, customers or prospective romantic partners. The negative side is that their computers link people's data without any thought to the distress this might cause.
192.com used to have access to the full electoral roll but when the law changed in 2003, and we could all opt out of being in the public register, 192 took the Government to court to claim that the new law was 'irrational.' The company lost the case: http://www.out-law.com/page-3865. You and I (sensibly) opted out of the public register from 2003 onwards, but some of your neighbours have yet to choose to do that.
As a result of the change in the law, the only full register to which companies like 192 have legal access is the 2002 electoral roll and some have chosen to continue to use it. That decision probably made sense in 2004 but less so now and their competitors make much of how out of date some datasets are these days.
The wider problem is that the Electoral Roll 2002 is a public document and other companies may get hold of it in the future. If they aren't UK companies, or are operating without a traceable postal address, there will be little you or I can do about it. However, I'm going to take this further and see what might be done to stop the councils in the UK from making old data available.
On the positive side, it would be a very, very odd combination of circumstances that would bring someone to the Google search that you found. However, if for example a neighbour decided to change energy supplier or you changed your car insurance then conceivably the 192 data might turn up in a standard credit search. But in cases like that companies will want to see a full address and so will use a proper credit agency to check that you really exist. I'm sure banks, energy companies and insurance firms know all about 192.com.
People don't believe everything they see on the Internet but companies and government agencies are becoming increasingly suspicious of people who have no internet presence at all. It is therefore probably a good idea to put an internet profile out there yourself on a reputable professional contacts site. This would be a profile over which you would have full control and it would turn up higher up a Google search than the rubbish datsets put together by the mindless computers of directory sites. This way anyone from your past who is searching for you, just like you're searching for them, will find proper, useful information and a secure contact form - people can send you a message through the website but aren't given your email address.
I think the best site to use is Linkedin http://www.linkedin.com/. It's free and has a very good reputation. It is secure and they won't do anything naughty with your information but admittedly it is set up for workplace contacts so you may have to be a little inventive when filling in the data fields. There are other options but give Linkedin some thought.
Having a prominent profile on a well-Googled site like Linkedin in certainly a step towards making yourself findable. Of course, those of your contemporaries less Interweb-savvy than you won't have a web presence at all so we're back to relying on old copies of the Electoral Roll. Most unsatisfactory. Perhaps a tv programme or a tv presenter could help to start a Linkedin revolution among the retired population. Maybe they could start a campaign against 192's use of old data. What programmes are most likely to be watched by the people you're trying to reach?
I hope this helps to put your mind at rest. I wish I could think of cleverer ways of helping you catch up with the people you've known in the past. I can see that it's like having read the opening chapter of lots of books - it would be good to know how the stories end.
All my love