data driven testing is nothing but retesting implemented in 
Qtp.

Data Driven testing is testing the functionality with 
dynamic input from QTP. When we record, the value we use 
become static. In Data driven test we convert that static 
value to dynamic so that we can give as many inputs we want 
to see the functionality is working ofr different inputs.

Data driven testing is very much useful while we are 
parameterising our test.Data driven testing means 
collecting the data from various sources like flat files,xl 
files and from databases and testing the functionalities of 
the application with this data by parameterisation

data driven testing is the parametrization of our test in
which we pick the no and iteration one by one and then
execute  them....
plz make me right if i m wrong.....

The Exection of an automation program on a software build 
with multiple test data is called as "data driven testing"