Websockets and external API

If I had a website that currently uses the PHP Basecamp API to request data from a basecamp account and feed it to my client application, how would that benefit HTML5 websites? Or maybe this is not the case at all.

My understanding would be that this process allows bi-directional socket communication, allowing real-time updates and notifications. those. the user edits the comment through my client application and the user in basecamp will see this change in real time. Is this correct or am I barking the wrong tree? Correct me if I am wrong, but Basecamp will require something along the Node.js line to open this two way connection?

Here's an example of a chat using similar techniques:

http://www.martinsikora.com/nodejs-and-websocket-simple-chat-tutorial

Greetings