1. A method for detecting an event from a social stream, the method comprising the steps of: receiving a social stream from a social networks; wherein said social stream comprises at least one object; and wherein said object comprises a text, sender information of said text, and recipient information of said text; clustering each object; monitoring changes in at least one of said clusters; and triggering an alarm when said changes in at least one of said clusters exceed a first threshold value; assigning said object to an existing cluster if a similarity value between said object and said existing cluster is greater than a second threshold value; creating a new cluster with said object if said similarity value between said object and said existing cluster is less than a second threshold value; and replacing a stale cluster with said new cluster; wherein said similarity value is determined by calculating a structural similarity value and a value selected from a group consisting of content-based similarity value, temporal similarity value and combinations thereof, wherein said structural similarity value is calculated by using structural components of said social network; and wherein said structural components comprises nodes and node frequencies; wherein at least one of the steps is carried out using a computer device.