On Facebook, I've got my real-life friends there but also subscribers which are usually IT people. Can I post something and make it visible only to subscribers and my "IT friends" (a list)? I don't want my regular friends to see technical posts.
To some extent, yes. When writing a post, if you click on the gear icon, you can set custom privacy settings for the post, to include/exclude specific lists and networks.
However, Facebook's About page for the Subscribe Button states:
Subscribers can see only the things you share publicly. They can also choose how many and what types of these public updates they get.
So you may not be able to explicitly include your Subscribers in this list. (I don't have Subscribers set up; you'll have to try it.)