Using Terminal to connect and use chat functionality of social networks

You better not look in the /bin folder then - that is one of the places where all sorts of little programs that the Terminal can use are installed. And don't even think about perusing the Mac OS X Manual pages, since that might give you an idea as to how many of those little programs to do the simplest tasks there are.

There is talk, but for the mentioned sites you will probably need to install some kind of client, if one is even available (since most everything is more visual than the Terminal).

You might be able to use something like Lynx

<http://www.macupdate.com/app/mac/18252/lynx>

which is a text only browser that can run from a terminal.

Lynx would allow you access social web sites.

Not sure if you could use web based chat programs as some of those are based on Javascript or java that might not run well from a terminal session.

There are command-line IRC clients available for various platforms including OS X, but you'll have to find, download, build and maintain them yourself; little like this is installed as part of OS X.

There's the fbcmd tool around that allows access to Facebook, with a write-up or two posted around the 'net. Whether that ports to OS X, I don't know.

Other protocols can have other tools.

There's probably a command-line Jabber client, but I haven't looked. Jabber is the text-messaging protocol underneath iChat and related tools

To build (and potentially port) various of the available source code tools to OS X, you'll likely need to download Xcode, and to specifically also install the command-line developer tools. (Though you might find tools written in a language such as Python, and that's available on OS X.)

And FWIW, Unix is built on the premise of a whole lot of little programs chained together to solve larger problems, too; that's the basis for OS X, and you'll see a whole lot of that as you start writing shell scripts.

You should try Irssi http://irssi.org/