I am trying to create a notification system very much like the SO one ( the one when receiving a new message ). My site is built in PHP and i would like the notifications to occur when data is inserted to the DB from the PHP.

At the top of my head i would just curl the node server passing it some post parameters, is that right way to do?

Are there any good practice (security, performances..)?

Look at the redis channels. We use this practice for same prupose. Benefits : you can have a lot of node.js servers and they will receive notifications almost a the same time...