Collecting data of visitors is not illegal as far as I know. If you visit this site and you don't use any IP spoofing, then the Larians can log your IP number, they can log the site you were coming from (if you use the same browser window), they can log where you are going to when you leave and they can log which pages you visited on this site.
Over time they can get determine from which site most people are redirected from and they can establish which external sites are most important to them.
All of this is strictly based on your IP address and the invisible information all browsers send as part of their header information. The information entails such info as your browser, operating system, window size and more stuff like that. The purpose of that is that it would allow the site builder to see what browser/OS/screen size people use most and optimize for that. Or check if anyone is still using 800x600 and if you still need to support that for your site.
E-mails have a whole bunch of 'invisible' data and so do browsers. Like anything it can be used in an innocent way and a harmfull way. An IP address says not much. You can derive the country of the person visiting and the ISP they are using. Unless the ISP tells you, there is no way to find out who is actually using this IP address.
But you actually post here and your IP address is stored with your post, that makes a link to more personal information and your browsing behavior based on your IP address. Eventhough I doubt the Larians actually would invest the time to get this info out of the system it is possible. Whenever you login somewhere a link can be made.
It gets even more trickier with cookies. Cookies can be reused. So if an ads provider on site X stores a cookie then that same ads provider can check on site Y if you visited other sites as well and how often you clicked on an ad and on which ad etc. etc.
You simply can not hide on the internet. That is good for tracking down criminals. It might not be so good for the average person though.
