Does Facebook listen my talks?

Listens or not you are the product if you use it.

Here's another site where a US professor "tested" this feature to see if Facebook was "monitoring" her conversations.

Just think of this: FB is free, but FB has a business plan. So, what is their source of revenue? Ads. How do they optimize ad revenue? They obviously use what they have: your personal data, which is the key to increase advertising efficiency.

Now it's probably basically for marketing purposes only. Not for political, ideological or philosophic matters. So, you may use FB if being profiled for marketing purposes is not a problem for you.

On the other hand, FB is an American company and you don't know who will rule the United States next year...

Footnote: you may of course replace FB with Google, Skype etc.

@objectifnul - While you are right that they use personal data for "marketing" purposes, you are mistaken that it is not used for "political, ideological or philosophic matters" (in your words). See this article - Facebook Accused of Censoring Conservatives - as one of the examples of how Facebook tries using "social maketing" to manipulate you. Also, politics involves marketing too. So I don't understand how you came to the conclusion that Facebook won't use your personal data to show political ads to you?

@sifartech Of course FB (just like Apple) is far from neutral and has a prudish and antiquated view of appropriateness. This is an additional and different issue. We are discussing of privacy: FB is spying on you because that's part of their business plan. And yes, the political, judicial spheres might be tempted in a near future to use their know-how for their own purposes (that's what will happen when an "I" will be appended to their acronym).

Besides, the whole internet is under surveillance. The difference with FB is this: we know there is no privacy with FB, we know who is watching and we know why.