(If you're a developer, the Developers page has the information you're looking for.)
The first step is to create a webhook in your account with Posting, Webhooks, Add New Webhook in the menu. Take note of the red URL of the webhook. You will need that later.
The second step is to register a free account at ifttt.com.
Once logged in to your ifttt.com account, do the following:
POST
.application/json
.REPLACE
text by using the Add ingredient button below the Body field. Do not remove any of the quotes characters. (The "ingredient" will vary depending on the source that you chose in the this step above.)The ifttt.com applet may take up to several hours before it starts doing its work. Use the Activity entry in the ifttt.com top menu to see if the applet has run or not.
Select the code depending on the social network that your webhook is publishing to.
{
"body": "REPLACE"
}
{
"title": "REPLACE",
"body": "REPLACE"
}