[garethrowlands]

Absolutely.

It's often helpful to distinguish between effects and side-effects. The idea is that an effect is deliberate and explicit, such as, say, sending an email or moving a robot's arm. Whereas a side-effect is one that happens but wasn't your explicit objective - heating the CPU, say, or silently caching a value in thread-local storage. Haskell programs often use the type system to make these kinds of distinction.