"It's just a basic search (like Ctrl + F).
For example, if there's a story called "ChatGPT's API Is So Good and Cheap, It Makes Most Text Generating AI Obsolete" and I have the keyword "GPT", I'll receive it in my feed because the title contains "GPT" in it.
There's also a "-whole-word" option, means it will match if the keyword is a whole word. I use it for monitoring stories with "AI" in the title.
