If I like an organisation or company on FB, does that mean they can automatically read what I post on my FB? Never thought about that, never cared much, until recently about one specific organisation.

I got it set up that friends from friends can read/react, not everyone.

Anyone know the answer?

idk but i don't think so.

The security setup on FB changes frequently and you have to revised them and change them yourself all the time.

As for the companies you like reading your posts, what FB does is called directive advertizing. Because you like that company, or used a game, or bought something from them or clicked on their ad, FB will then have a log of companies you like. When they have ADs for those companies, they will more likely place them in your page because they know you "liked" them. Google, Yahoo, and others do it by knowing key words on your emails. Seriously. Maybe FB is doing that from the posts.

I help some people change their preferences on FB but I do not have FB myself anymore. Too much hassle.

I do block the ads from Google, Yahoo, etc.: all of them! lol

As far as "Liked" pages go - no, they shouldn't be able to read YOUR posts unless you post directly on their page. In some cases, though, it will ask you if the Group/Company/Liked Object can see:
Your email.
Your birthday.
Your Friends list.
Etc, etc.

Check before you allow these, as some of them want to get VERY nosey about the whole thing. (For example, they might try to use your Friends List to post advertisements on your friends' pages - it's pretty much a chain letter.)

Most companies won't even allow random FaceBook people to posts on their page - the closest you can do is Send a Message to the FaceBook group site, which may or probably will not be actually read by a human being. Liked pages will not automatically receive your Wall posts, or private messages, or anything like that. Or if they are, something is deeply wrong and you should contact FaceBook help services directly.

As of Jan.1 , 2015 , Facebook has a new privacy policy that you agreed to or your profile gets deleted . In essence , you agreed to give FB complete access to any and all devices you use to participate on their site . They sell your data to 3rd party advertisers for a profit and target ads specifically to your profile in the possibility of you purchasing a product . it is very invasive and a complete disregard for your privacy in my opinion . Just visiting Facebook and not posting anything lets them go through your phone , computer or whatever you use . I no longer go on the personal account as I firmly believe it's none of Facebook's business what my personal data is and it is not for sale to the highest bidder . There are social media sites like Ello or tsu.co that do not go sticking ther nose where it doesn't belong . I feel the Facebook wankers have made enough money and sneaky , underhand practices like this are completely unacceptable to me so screw them . As an added bonus , the US government also monitors your interaction to determine your "threat level".Um , no thanks . I'm not a terrorist or a dangerous violent criminal but I'd rather not have US Marshalls or FBI agents showing up at my door because they thought I said the wrong thing on a silly , drama ridden site that amounts to a whole lot of nothing to begin with . A nice little forum like this will do just fine to get my social media fix if I need one and not some giant faceless greedy corporation like Facebook . If you give them an inch , they will take a mile so don't give them an inch to begin with. Google " Facebook New Privacy Policy" and everything I stated here is in black & white.

http://www.snopes.com/computer/facebook/fbspying.asp

you all keep your Pants on,you hear?