The targeted text advertising you see in the sidebar column is what's called Google Adsense advertising. Advertisers only pay when potential customers, ie you, click on the ads, and the site owner, ie me, then gets a pittance of commission (we're talking pennies). The fact that Google, under its nom de plume Blogspot, provides the blog hosting service is only incidental — advertising is optional and absent by default. You can put Adsense advertising on any web page you manage.
Our modest aim is to accrue enough revenue to buy some premium dog biscuits for Ninotchka, mascot of another blog, NINOTCHKA'S OCCASIONAL BLOG, q.v.