Sneak reading my e-mail

I am kind of upset about the way that the different internet platforms sneak read my e-mails etc. I am referring to the directed marketing on the sites. I find it kind of ok that the ad here on the blog somehow reflect what I write about in the posts, it is kind of part of the deal. But what makes me upset is when the content of my e-mails obviously is scanned to direct advertisement to me on gmail. Just take a few examples: while planning the wedding of a friend and through e-mails discussing what gift to buy to the couple, I noticed that the ads all of a sudden where about wedding presents. Today I received an e-mail about a available apartment from a landlord where I have registered on a waiting list. Then I noticed ads about apartments, moving and furniture etc. As gmail and blogger are connected I even think they “cross read” their clients’ information. I suspect this because there also was an ad about rental apartments in Rome on my gmail account. I don’t really approve of this!! Although I feel quite sure this is done automatically, it feels like an infringement on my privacy.