i have put Article to www.propeller.com with my site name. After half an hour i typed my site name in google search box then that article link displayed in the SERP. But After 2-3 hours i did same thing. But didn't display previous link. Why is that?...what happened to it?
You may have hit different data canters on Google's end. The datacenters don't all update at the same time. One center had the data while the other one didn't. If you google for "google compare datacenter results" you should discover some datacenter comparison sites.