What Is PQWL - Pooled Quota Waiting List ?

Today I went to book train ticket from Chennai To Madurai and unfortunately there were no tickets available and decided to go for wait listed e ticket on irctc web site. Surprisingly after booking on my e-ticket status of my ticket shown as PQWL. Initially I was wondered and don't know what it is, then done some research on types of wait listed tickets.This is what I found out.

A Pooled Quota Waiting List ('PQWL') is shared by several small stations in a particular region. E.g., Tiruppur, Salem, etc., share in the quota and wait list for some trains originating from Trivandrum or Mangalore. As another example, the 2723 Andhra Pradesh Exp. has three quotas, for Secunderabad - New Delhi, Secunderabad - nagpur, and Secunderabad - Bhopal. There is also a pooled quota for passengers travelling from Secunderabad to stations beyond Bhopal but short of Jhansi. If this quota is exhausted, a passenger is placed in the pooled quota waiting list. Pooled Quotas normally operate only from the originating station of a route, and there is only one Pooled Quota for the entire run. The Pooled Quota is intended to be utilized by passengers travelling from the originating station to a station short of the terminating station, or from an intermediate station to the terminating station, or between two intermediate stations. Such remote location quotas are also provided when there is a very strong demand for the train in question, because of which, without such additional quotas, all seats or berths might be fully consumed by passengers from the originating station leaving nothing available for those wishing to travel from intermediate points. Vacant Pooled Quota berths are automatically tapped by the PRS for booking end-to-end passengers. Passengers in the Pooled Quota Waiting List are cleared against the vacancies in the earmarked Pooled Quota only, or against General Quota vacancies available at the time of charting.