The fact that "here" is a widely used word does matter. What Nokia's trademark buys them is the right to name a product or business "here". It doesn't given them ownership of the word "here" when used with it's descriptive meaning, whether or not that use occurs in a similar product/business context. Given that the offending app allows people to notify others that they are "here", it's open to debate as to whether or not their use of the word is "merely descriptive". It's unlikely though.
I agree that it probably would have been wise for the startup to avoid using that name, but they could well be within their rights to. Own the downside: should that be permitted, it guarantees that they won't be able to protect the name themselves either.
The fact that "here" is a widely used word does matter. What Nokia's trademark buys them is the right to name a product or business "here". It doesn't given them ownership of the word "here" when used with it's descriptive meaning, whether or not that use occurs in a similar product/business context.
OK, but how is an app called Here merely using the word for its descriptive meaning?
If you were only referring to the Here button in the other app made by the start-up, then I agree there seems to be some room for interpretation. Even then, though, if the fundamental justification for protecting trademarks and having related laws about "passing off" is to ensure that customers aren't duped into thinking they're dealing with someone else, an app that is named one thing but uses a related app's name so prominently in its UI seems to be at best a grey area.
I agree that it probably would have been wise for the startup to avoid using that name, but they could well be within their rights to. Own the downside: should that be permitted, it guarantees that they won't be able to protect the name themselves either.