ML notes : linear regression vs logistic regression

In the linear regression model the dependent(output) variable y is
considered continuous, whereas in logistic regression it is
categorical, i.e., discrete. In application, the former is used in
regression settings while the latter is used for binary classification
or multi-class classification (where it is called multinomial logistic
regression)

http://stats.stackexchange.com/questions/29325/what-is-the-difference-between-linear-regression-and-logistic-regression