Tomorrow morning (UK time) we will be updating the operating system on the server this blog and website runs on. Service may be intermittent as we're going to have to reboot it at least once. (In case you're wondering it's on Debian Stable, but an old release thereof—so it's time to blow off the cobwebs and bring it up to date.)
[this stage is now completed]
Some time in October the server is going to be switched off and spend about six hours overnight in the back of a truck as it is moved to a new hosting centre. I'll give you some more warning in the days before the move. Note that this is "overnight" in UK time, so it'll be an afternoon outage for most of you.
Next, Google have (un-)helpfully announced that, in an attempt to drive the internet onto SSL (to reduce third-party snooping) they are soon going to begin down-ranking search results from non-encrypted web servers (i.e. results obtained over HTTP, not HTTPS).
Now, speaking personally, this is an inconvenience to me. My blog is public, and if you post a comment on it you are posting it with the expectation of it being read by all and sundry. I don't need a secure server for what I do on the web: I'm not running an e-commerce site.
However, I'm all in favour of reducing corporate and government snooping on the open internet. And I'm all in favour of my blog still featuring high in the search results when you hunt for my name.
So, once we've done the operating system upgrade, we will be adding a multi-homed SSL-capable web server to this system. Once we're done you will be able to find the blog via https://www.accelerando.org/ as well as http://www.accelerando.org. (We'll probably make some other changes, too, including allowing you to leave out the www prefix. Shocking, I know.)
However. This machine provides web services for multiple domains, and in order to provide a secure web service for multiple virtual hosts with only one IP address (they're in short supply) we have to use a server-side extension called SNI. SNI is not supported by some older web browsers, notably Internet Explorer 6 on any operating system, or IE running on Windows XP, or Safari on XP.
Let me emphasize that the site will remain fully accessible and functional via unencrypted HTTP, just like you're using right now. However, if you want to thumb your nose at the NSA and for some reason insist on running Windows XP, you'll need to grab a copy of Firefox or Opera.