For someone who does a blog or website for commercial reasons, advertising may be a necessary form of revenue. When it's offered to all of us, it sounds like a good deal. That deal being if anyone visiting your site enters one of the advertisements through your page, you get a stipend. Sounds like easy money.
Upon investigation of the offer, I found the owners of the web site or the blog agency will choose what advertisements appear on your site. They promise they will all be relative to your topic. And let the creepiness begin.
I visited several garden blogs and web pages and was appalled at what someone thought was relative to the garden topic. Graphic medical problems (and quack cures), infra-commercials of every crazy thing available during the middle of the night on TV, political advertisements from the highest contributor and the list goes on.
Some of the advertisements had videos so distracting it was hard to read the printed material without getting car sick. One site had the advertisements scattered throughout the text to the point I was never sure when it was a part of the article or junk.
I also don't want to be beholding or indebted to a paid advertiser. Should an advertiser on my little blog try to sell garden pruners that I've found are junk - I don't want to feel pressured to say anything other than "they're junk."
I know some web sites and blogs must rely on these advertisements and I feel really sorry for what they have to endure. Should I want all the bells and whistles on my pages for a larger consumer market, I would have to sink lots more money into my little reading material. I have the option of not really caring if one or one-million want to read what I write.
I like to compare my writing to someone who knits and gives it away or wraps it around tree trunks because what they are enjoying is the doing.
I've been blessed that I can do this without advertising and outside oversight. Hope that works for you, too.