I think Twitter is great to understand what a person is about if an appropriate number of tweets are taken in context. Fairly certain if a person tweets about Python all day, then they probably care about Python.
Then there is a qualitative analysis to be done, is the person tweeting also the person writing the content they are sharing? Are they even blogging about the subject? Are they active in anyway surrounding topic A outside twitter (github, stack overflow, etc)?
Then you can also look into who they follow and who follows them, but then you would be stalking on a whole new level 👀