Don't count on it. Steemit needs much more revenue than advertising will offer. If we're lucky, they might use the ad income to develop more features or to sell less Steem.
But you're free to sell your own ads in your posts. An easy way to include ads is @dclick. This has the advantage that you keep receiving small payments for your posts after 7 days.
The Steemit Inc adopted the ads system as a means of generating more income for the Steemit company. The fact is that some of the money generated from the ads are being used for the development of the steem blockchain and sometimes payment of workers. I am quite sure you are also experiencing the great development occurring on the steem blockchain as a result of the great impact and work of Steemit Inc.
There are lots of projects proposed by Steemit Inc for the betterment of the Steemit community but revenue will be needed to execute such plans. One of the ways of generating income into the steem blockchain is by making use of ads even though this will generate some amount of income required by the Steemit team to keep the platform running.
In conclusion, Steemit users aren't really get any share from the ads directly but we are automatically getting the share through the development of the steem blockchain. Remember that every Steemians makes up the Steemit community and every work done by Steemit Inc is to make the Steemit platform more better and beneficial for everyone of us. Since the Steemit platform is undergoing lot of development which seems to be beneficial for us, I will say we are also benefiting from the ads indirectly.
Thanks for reading and I hope this helps.