I'm trying to understand how similarities in trademarks are dealt with. To take an example (that I used in a previous unrelated question), assuming a trademark existed for "BodyLife", a company trying to help people improve their health through exercise, would a similar company be able to register and use a trademark like "BodyForLife"?
I'm interested in how a one word difference plays.
How are those conflicts resolved? Is it the trademark bureau to accept or not accept (and can this decision be appealed), or is it done mostly through litigation?
Note that every country has different trademark laws, so even if this is acceptable in your country (I assume you are from the US) you may find your business to be illegal if you ever open an office in another country or relocate.
Also, even if it's ok from trademark law point of view, there are probably many other laws that can be used by them to sue you if they want.
And last but not least, if you ever become more successful than them - you will lose customers that mistakenly get to them instead of you.
I would stay away from such situations even if it was legal.
The trademark law in the US is as clear as mud on most of this stuff. For a trademark, the following tests apply:
Since the whole purpose of trademarks is to identify different products and services, they need to be distinctive and non-confusing from other marks. In broad terms, trademarks fall into four categories: (1) arbitrary or fanciful, (2) suggestive, (3) descriptive, or (4) generic. Each category has specific rules, which I will not get into. The thing to remember is that trademarks or service marks are meant to be associated with some product or service so people can relate that back to the company that provides the product or service. The more distinctive and unique, the better.
The PTO wants trademarks to assist the customer in identify products or services that relate back to a company. Any confusion will just make it harder to get.