According to Google your search history changes the results you’re seeing on Google. Although the search history is not a direct ranking it’s used by Google to personalize the search results.

Starting 2009, Google began personalizing search results for everyone, based on search history:

” For example, since I always search for [recipes] and often click on results from epicurious.com, Google might rank epicurious.com higher on the results page the next time I look for recipes. Other times, when I’m looking for news about Cornell University’s sports teams, I search for [big red]. Because I frequently click on www.cornellbigred.com, Google might show me this result first, instead of the Big Red soda company or others.” official statement source.

So, if you search for “ecommerce SEO”, then click and engage with my website, your future searches related to ecommerce and SEO will personalize the results by giving more weight to this website.