Hi Piet,
Now you hit upon an interesting issue. In NL we were more or less forced a couple of years ago to open up registration for private persons too, the reasoning behind it being 'fixed' e-mail addresses even when people moved to another ISP, which happened frequently. Initially we 'solved' this by introducing numeric SLD's (123.nl), under which they could register names. That was not a success, to put it mildly: all in all we registered less than 1000 domains of that kind. Main reason: people didn't like the numeric "extension". More recently .NL itself was opened up for private persons too, but now we see a vastly different situation from a couple of years ago: because of the massive amounts of spam 'fixed' addresses are not en vogue anymore and lots of people have loads of addresses. Which is just one reason why I don't expect TLD's to explode and a good example of a problem that solves itself.
Interesting. While I've many times have seen spam described as a problem this it the first time ever I've seen it described as a solution to another problem ;-) Johan