It’s still not entirely clear what the UK government wants to gather — it has been understandably evasive on this front — but it would seem to include things like recipients of emails, Skype contacts and addresses of Web sites visited (possibly even full URLs, which will point to very specific content.) But the details don’t really matter, because this is actually a question of principle.
The UK government, like the Swedish government before it, is trying to set up a false equivalence between monitoring communications before the Internet became a mass medium, and after. But the intrusiveness of such surveillance before the Internet, and before computing power was available to analyze the data gathered, was limited. Back then, working out the network of contacts of a person of interest could be done, but with effort, and at some cost. This ensured that only the potentially most serious threats were investigated.
But once again, Moore’s Law has changed everything. What the UK government wishes to gather would allow the entire social graph of everyone in the UK to be calculated in near real-time. It would mean that their every move online could be watched as it happened, and cross-referenced with their past communications history. As Falkvinge points out in another recent post, what has really changed is not so much the ability to spy, but the cost of doing so.
Today, thanks to our networked lives and the plummeting cost of hardware, national governments can monitor everything we do online for the same outlay as the much more limited surveillance of yesteryear. So what is really being preserved is not some supposedly circumscribed spying capability, but the orders-of-magnitude cost. By keeping that cost constant, governments can increase the scope of their spying hugely.