You  are online writer / blogger and also want to reach your writings to your known & unknown readers then you must update search engines and blog directories / registries by yourself. Some people thinking that google will update itself. But it can takes a week or a month. Apart from this there's a quicker way to do it & that is PING sites.
Pinging is a process by which you can inform major search engines and RSS directories (like Google, Yahoo etc) that you have updated content in your blog/website. It will help your blog/website getting indexed fast and will increase your traffic to a large extent.

Here are some list of twenty Ping sites which will help you to get Ping your blog / website to all notable search engines and blog directories, making your blog/website more visible and accessible to your readers.
i) Google Ping
ii) Pingler
iii) Ping-O-Matic
iv) Google Blogsearch
v) Bulk Ping
vi) Ping Farm
vii) Feed Shark
viii)  Ping My Blog
ix)  Pingates
x)  Ping That Blog
xi) My Pagerank
xii) Twingly
xiii) Yandex
xiv) Pingoat
xv)  Blogbuzzer
xvi) Totalping
xvii)  Ping
xviii)  Blog ping tool
xix)  Auto Ping
xx)  Ping My URL

Remember use these sites only you have updated your posts or page on your blog/website. Too many pings are penalized by Google and it will have the opposite effect on your blog/website. Gudluck & happy pinging.