Translation is simply the act of transforming a message from one language to another. The mission of a skilled translator is to translate source text in such a way that the finished product reads as if it has been written in the source language. A translation will make the target text available and accessible to a broader group of people than a localisation will do.
However, some target texts need to be adapted to the target audience. This is becoming more and more important for advertising texts and other marketing related content.
In a world with an increasing amount of automated translations (by e.g. Google, Trados), every online publisher needs to stand out from the crowd with content that makes sense to locals, and is attractive enough for them to read!