I hear Jimmy Fallon saying, "Thank you, AdBlock Plus, for removing those annoying, unnerving ads that read my emails before I do." So have you ever noticed the advertising in Gmail or Facebook that "know" the keywords in the message?
Firefox was the first browser that had an extension (think, "App") that would prevent virtually all advertising as you surf the Web. Chrome has had it since 2010 and similar AdBlock add-ons for Internet Explorer & Safari are available.
I highly recommend adding AdBlock Plus to your browser.