I have my own domains, but they're forwarded to my ISP's email service. Result is the same. I can switch ISPs without changing my email address. Although I would have to change the forwarding. As for my ISP's spam filter: It's overzealous, so I turned it off. It should be off unless BT have decided to turn it on again behind my back.
For those that are interested: I use disposable email addresses and I don't get enough spam to need a spam filter. When I do get spam, the unsubscribe links work. The only exception to this was due to a compromised gaming website. The email I'd used for their forum started to receive spam. So it was a simple case of deleting that email address. The email was site-unique. Of course the time spent managing my email addresses might well exceed the time I would otherwise have spent shifting through spam...
It's a consequence of the laws of statistical thermodynamics: That entropy always increases. There is a practically zero chance of entropy decreasing, and intelligence would need to exist in an area of decreasing entropy all the time. The chance of this is zero. Boltzmann brains are consequence of entropy decreasing, but these would survive for even shorter periods on average, as the universe they exist in will be closer to maximum entropy (on average).
One exception I can see to this, is if the state space of the universe increases. If it does then a maximum entropy state might never be reached. Anyone know enough about inflation and gravity to say if this is true for a universe that increases in size?