Communication with readers

Not sure if this is the right area to post this thread so feel free to move it if necessary.

Currently I am about to finish my first ebook, which is a little collection of articles about this and that.
Every now and then I directly adress the reader to voice his opinion on the subject matter.
At first I just prompted to send me an e-mail, but then I thought a discussion with other readers would be more rewarding. But I am puzzled which social network to use for that. Facebook? Twitter?

Or should I drop the idea entirely?
Maybe some of you already made experiences with such an attempt and can help me out with that.

Yeah I guess you are right. I already have a website but am too lazy too keep it up to date. In the following weeks I will just have to put some effort into it.