I'll quote our friends at ToffeeWeb;
Which ads are delivered to a particular user are based on a combination of factors relating to the browser in which the website is being used – e.g. geographic location, browsing and search history, etc. Google uses that information to tailor many of the ads to a given user; we at ToffeeWeb play no role in selecting which ads you see, although we are able to filter out ads that we deem unsuitable to our readers.
If you see an ad promoting either a rival club or inappropriate material, contact us so that we can make an assessment and take measures to filter the ad in question out if we deem if to be unsuitable for our viewers.
I just refreshed this page 10 times and got ads for these :
Sky TV
Paypal card reader
Shakespeare in love
Hunter clothing
NFU Mutual home insurance
Longleat safari park
Heavy duty storage shelters
Vodafone
Ebay
Subaru XV crossover
Is it all my search history in the entire time i've been using this browser?
Depends how generic the links are as well. I have searched for sky on google and probably viewed offers for vodafone phones when looking for a new one.
I've searched for cars and may have looked at a page with a Subaru on.
I've looked at clothes but not that particular brand (Hunters).
I probably looked at car insurance (but not home insurance).
Don't remember ever looking at shakepspeare in love or storage shelters.
So how accurate compared to my actual interests are these adverts.
Bit like if you now start getting targetted ads for male clothing shops cause you used the word"tailor" in your post.
I know its not an exact science, and you might not actually know and are just going by what google say, but it just doesn't seem very accurate to me, and certainly not based on what i usually browse.