Well, think it like this when you are on facebook and if you are seeing that your firend is online and you want to start a chat then what you do at first is saying "hi" in the chat box which means pining to know wether he's available or not ! So, I guess now you can draw the idea what pining is !
Google’s Blogger service, often referenced to by its Blogspot domain, provides organization owners with many alternatives for promoting their blogs and informing the public about blog updates, a process known as "pinging."
@harrykingsville There are many Pinging tools available as you can just search it on the web.
Here are a few:
Hope this might be useful for better indexing of your blogs.