The product is different from wikis or intranets because it's not just about anticipating what someone might need and documenting that. Stack Overflow for Teams gives users the ability to ask a question and people can ask teammates to add knowledge to the platform right in chat. So knowledge itself can be either proactively added, meaning people are anticipating needs, or it can be reactively added, based on an immediate need, like a question.
For your search question - it has basic and advanced search capabilities. You can read more about that here.
https://stackoverflow.help/en/articles/4400196-search-existi...
If you want to read about how it compares to using version control, Confluence, or wikis, there is a case study on switching from those tools here.
https://info.stackoverflowsolutions.com/Enterprise_Elastic-C...