Google's an advertising company. Of course they were going to add adverts. Even if the original founders still ran the site it'd probably eventually have gotten adverts. Bandwidth isn't free, especially at that scale. You expect Google to run it out of the love of their hearts after paying a huge sum to buy it?
If you don't like the adverts, just use Adblock Plus/uBlock Origin and call it a day.
Google's an advertising company. Of course they were going to add adverts. Even if the original founders still ran the site it'd probably eventually have gotten adverts. Bandwidth isn't free, especially at that scale. You expect Google to run it out of the love of their hearts after paying a huge sum to buy it?
If you don't like the adverts, just use Adblock Plus/uBlock Origin and call it a day.