Here's a privacy-enhancing technology for you to consider:

"No."

You don't need to know. You don't need to measure. The efficacy of advertising campaigns, market segmentation, and relevance targeting should be minimized for the good of humanity.

my advice to students is usually something like: the trend is short, your life is long. research what you are interested in, and make sure you can explain why you are doing it to other researchers (and to beancounters when necessary).

this is especially important for phd students: if you do a "trend project" for your phd, it will be both out of date and "cringe" by the time you hit the job market.