We discovered this hack a couple of months ago. We hadn't realised how powerful HubSpots search functionality is across notes. With this discovery we started to use Hashtags, to help find certain information faster.
Our best use case of this has been how we now ensure product feedback is recongnised with a hashtag so that it's easily searchable in HubSpot and any team member can use it.
I have put togther a short video below detailing how this works: