Even from their announcement blog post, they're intentionally mixing words -
https://www.confluent.io/blog/exactly-once-semantics-are-pos...They may never describe Kafka itself without the word "semantics", but here are some other snippets:
- "I know what some of you are thinking. Exactly once delivery is impossible"
- "While some have outright said that exactly once delivery is probably impossible!"
They mix their phrasing depending on what they're talking about, and whether they are referring to Kafka directly or indirectly.