Sometimes, when I post a question, someone might come and post a comment, that does not necessarily belong to the context. I would like then, to reply in a chat room, rather than another comment.
How can I do that?
Anyone with 100 reputation can create a chat room.
Note: Anyone can view a chat room; 20 reputation is required to talk in chat
When should I create a new chat room?
When you find yourself wanting to have an extended conversation about a topic that is not covered by one of the existing chat rooms, you should create a new room for it.
How do I create a new chat room?
There is a link to chat in the footer of every page. The link also appears in the Stack Exchange site switcher on the upper left corner of every page. Click one of those links, and then click the "create a new room" button at the bottom of the Rooms page.
What happens when I create a new room?
After you create the room, you'll want to invite other users into your room -- either using the invite room menu option, or by pasting the URL to your room as a chat message in other rooms you're participating in.
You can share the chat room URL with the broader internet, but bear in mind that only users who hold the chat privilege on the parent site will be able to talk in your room!
At 1,000 reputation, you can create a Gallery Chat Room:
What are gallery chat rooms?
Chat rooms are typically public and open to all. A gallery chat room allows anyone to enter, but only specific users may talk in the room, as determined by the room owner.
When should I create a gallery chat room?
When you wish to have a controlled conversation between specific community members, without anyone else interjecting.
How do I create a gallery chat room?
Visit: http://chat.stackexchange.com
Click create room, then select the gallery option. Visit the info panel of your room and use the access tab to grant talking privileges to other users.
What happens when another user enters the room?
They will be able to read the conversation in the room as it happens, but they will not be able to talk until you, as the room owner, grant them the rights to.
If you want to move existing comments to a chat room, flag any one of the comments for moderator attention and explain which comments you want moved.
If you experience any difficulty with your new chat room, flag for moderator attention, or ask for help from one of the experienced regular users in the main site chat room.
See also the chat FAQ.