system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: when a new company trademarks a logo, how does the trademark office know it’s a unique logo without manually reviewing millions of other logos?

Bonus points - how did they do this before they had computers to help?
gpt
Trademarks are only valid for the line of business it is actually for. For example using five rings to promote your sporting event is a big no-no because it resembled the olypmic rings. However using five rings to promote your line of sports drinks is fine, assuming nobody have registered a similar trademark to promote their line of sports drinks. This means that the patent office does not have to look through all logos to find similar ones but can limit themselves to one section. In addition any logos that is submited for trademarking requires a text description. This can be used to look up an index over already trademarked logos. In addition a granted trademark may be appealed if it can be shown to have been erroniously issued. So even if the patent office misses the similarities between two trademarked logos this may be resolved once these similarities are discovered later on.