Unfaithful vs Irreplaceable: more successful worldwide
Rihanna - Unfaithful: 226,474,106
Beyoncé - Irreplaceable: 137,670,062
I feel like Unfaithful had more impact, a lot of people are still listening to Unfaithful while Irreplaceable is already forgotten.
The fact Unfaithful has almost 100 million views more than it despite being an older song and from the time Rihanna wasn't even that big speaks volumes.