"following" is a mechanism, that is similar to twitter or facebook following.
- You need to include the space named: "following" into your space. This will include the needed plugins and templates.
Following a space:
To follow a space you just need to create a tiddler eg: @pmario and tag it: follow
- So the above setting would follow my space.
- You can see who I follow if you visit my space . The link shows a list of tiddlers I did tag follow.
- if you included the space: "following", there will be a new tiddler named: Activity.
- If you open this tidder, it will get a list of all public tiddlers from users / spaces you follow.
- So if you want to get my attention, you create a public tiddler in your space and tag it: @pmario
- So if I follow you, I get a "highlighted" list element in my activity stream.
- If I want to get your attention I would create a public tiddler in my space and tag it with @YourUsername
- If you follow me, you will get a highlighted list element ....
There is also a possibility to see if any user tagged a public tiddler with a username eg: @pmario. So you don't need to follow everyone, just to see if they want to get your attention ... I use the <<tscan...>> macro  to get a list of tiddlers that are tagged @pmario
The "following" space also contains some more usefull plugins.
- <<following>> .. tells you who someone is following
- <<followers>> .. can tell you, who follows whom
Some more info can be found at the "following" space 
The reply mechanism is meant for "communication" in a TS setting. ... But the way it implemented is quite different, to what users are used to ...
Let me explain:
In a "standard" eg Wordpress setting the owner of a blog may allow visitors to post comments "into" the blog owners space - database.
- So if I visit your blog, and you did enable comments, I can write my comments to your database or "pollute" it with spam if I'd be evil.
- This setting imo has at least 2 disadvantages.
a) You need to take care that you filter spam and "rude" comments. Which is a lot of work.
b) I'm not the owner of my comments any more, because they are on your server in your database and you are in control of it.
- So most people don't care about a) and b) .. may be they like spam or like to deal with it. I don't know.
How is TS different
- You have to create a space with your user-name. At this space you have "full access". So with default settings, you only can write to your own spaces.
- If you want to reply to one of my tiddlers, you give it the same name and tag it with eg: @pmario. So I can see it. "That's basically the TS reply mechanism"
- If I care about it, I create a filter, that "pulls" your public content into my space and it can be seen there.
- If I don't care ... I don't
See some examples:
I use a tiddler named "Topics" that show a list of my tiddlers, where I do pull content from other spaces
"Some more following thoughts" is one of them. 
The advantage here is, that I have control over my content and you stay in control of yours. Because your tiddler lives in your space, you can modify it or even remove it. ... If I decide I don't like your tiddler, I just exclude it from the list on my space. ... This mechanism is different, to what we are used to ....
In a wordpress setting, if I'd remove your comment on my blog, because I think it is rude, you could say I'm a moron, because you did take your time to post something valuable and I did destroy it at will. In a wordpress setting, you would be right, because I did violate your right, to own and express your thoughts. So imo the "design" is broken here. ... For me there is an "ethical" dilemma - If I want to respect your rights and if I want respect "free speech", I can't remove your comment. Even if it conflicts with my personal opinion (which is _my_ right). .... Can you see it .... Either you loose or I loose. ...
In a TS setting this is different.
- Your comments are stored on your space. You can do with them what ever you want.
- I'm in command of my space, and I can decide, what is shown there or not.
So imo we both win. You can write what ever you think about my "blog post" and I can decide, if I list it on my space or not. ... No dilema, we are both in command of our content.
There are 2 problems with the TS reply mechanism.
- There is no good UI, that let's you create a "traditional" discussion group / forum, with a "hierarchical" structure.
- probably, because TS isn't designed to be a discussion group.
- With the existing UI, it actually isn't possible.
- The TS mechanism doesn't allow anonymous posts, in a default setting. So that's why users seem to refuse it.
I think, we just didn't explore the TS possibilities enough. ... There is a very simple way to create a "news" or "what's new" system with TS . Which imo could be interesting for your usecase.
TS allows us to be the "owner" of our content, which is very rare in the web atm. But this ownership has a price: responsibility. TS makes it clear by design. You can't post to someone elses space, if you are not a member of this space. So your posts will stay in your space!
May be we are not willing to pay this price or we are just not used to it ;) But that's a different topic.