Googles long-term memory

Recently, I made an interesting discovery regarding Googles long-term memory. I was shopping for some RAM modules for my notebook and I wanted to find out, which modules exactly I needed. So, I googled. I found the correct type, used a price-comparison website, ordered a few and that was that.

But, a few days later, this appeared on a page I was visiting:

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A bit later, this one:

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And then this:

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And then these:

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Now, that's funny. Obviously, after I had bought some memory modules, I was definitely in the market for some more. Or maybe a hard drive (which wouldn't even fit into the notebook). It looks like Google has an impressive long-term memory, storing my "interesting" searches for quite a while, because I only got them to stop by opting-out of ad-tracking completely. No, I find this a waste of resources, because there's a difference here between events that occur only once, like shopping for hardware, and events that occur more often, like shopping for books or such things. And I think it's strange that Google cannot differentiate between the two. After all, this should show up rather obviously in click statistics.

However, this is the first time such a strange campaign targeted myself. Have any of you seen such things?