Two suggestions:
Look at how big companies like Amazon and Netflix program the see also or you might like parts of their search. I know when I buy something at Amazon I will get a list of related and possibly interesting things to look at. Some are related via words I use some by use. Netflix is getting better and better about accurately guessing how we will rate any given movie based on our ratings from the past.
Both I believe are using some form of heuristic programming software to do that.
I haven't loked at heuristic programming techniques in decades but I would expect that it has gone a bit further than when I last looked. Might be the search term to get you there...

