You may have gotten an email today from Codemasters about this, even though perhaps you don't remember ever registering anything on their websites. I know I thought that when I got the email, until I remembered I probably signed up for an APB beta ages ago.
Codemasters.com was breached on June 3rd, and as soon as it was detected Codemasters took the website and associated web services offline. Since then, an investigation into the scope of the breach showed that whoever hacked it was able to access the following.
While they couldn't verify if anything was actually downloaded, it's better to be safe than sorry. A new website will launch later in the year and Codemasters.com will redirect to the Facebook page for the time being -- although it doesn't do so yet.
Codemasters advise you to change your passwords (tip: if you store them, check your browser's stored passwords to see what you used), and to not be an idiot in general if you are asked for credit card info and whatnot.
Also: "The safest way to visit your favourite websites is always by typing in the address manually into the address bar of your browser."
[Thanks everyone who sent this in]