Side Note - Algorithms

So after our last discussion in class, I have realized a lot of algorithms. I've gotten so many e-mails from places where I have shopped online, mainly from Walmart. For the most part, I didn't even click on the e-mail because I'm sick of them sending me e-mails about what my interests might be. As a Cheesecake Factory employ, I had to recently invest in an iron and iron board from Walmart. Since then, I've been getting so many e-mails that were sort of related to those items that I've bought... so weird. It's true about these algorithms that convince the online consumers that they might need other materials that could be related to the recent items bought. This also goes for music. I use Pandora a lot because I get really lazy to put together playlists from my iTunes. Sometimes, Pandora is right on the money with the type of music I want to listen to but at times, it's SO wrong. It skipped from genre to another genre that was not related to the music I wanted to listen too. How does it go from classic rock to country? It doesn't make sense...