So the obvious answer is that you can’t get this for free. It’s all coding. It’s also not cheap.

Sure, Blogger is nice. LiveJournal is nice. But I want to make it clear that those are PUBLISHING PLATFORMS where you can write blog posts and articles and get them pushed out to the world. They do NOT have the interactivity required to build a real social network.

In addition, "free online website builders" will do one thing: give you static websites that do not have dynamic elements, and dynamic elements are what makes websites social (messaging, photos, wall posts, chat, etc.). If you want messaging, wall posts, the ability to upload videos, etc etc, you NEED to learn a programming language, like PHP or Ruby on Rails. You NEED to have web storage space that could cost anywhere from $20/month (if you have 2 users on the site) to $2 million a month (which is probably what YouTube and Facebook are paying — no joke — Facebook has 60,000 servers! Do you know how much one costs to maintain? Between $150 and $500). You also need to understand databases. And you can’t get that type of functionality with free online website builders.

I’m working on my own project right now and a site that has about 1/5 of the features of these sites is being quoted at $40,000.

I’m sorry to disappoint but your wishful thinking isn’t realistic.
References :
I have a LOT of experience in this. I worked at a web design company. My day job is actually "social media."

https://www.blogger.com/
– A great starting site to get a taste of blogging, very easy to use.

http://www.livejournal.com/
– Part social network, part blogging, all free.

http://www.zoomshare.com/
– Free blog hosting with 250MB of free storage.

OR

You can use Free Online Website Builders. Here are a few FREE ones…
http://www.yola.com/
http://www.webnode.com/
http://www.webstarts.com/
http://www.webs.com/

OR

You can use FREE website builder softwares.. Here are some you can download & use for FREE.
KompoZer : http://www.kompozer.net/
WebDwarf : http://www.virtualmechanics.com/products/dwarf/
Wizzypage : http://www.interannex.com/wizzyinfo/
References :