In retrospect, I understand that my initial response to OPs question was snarky to what was essentially a very valid question. I owe her an apology (some days are just bad)
Use Cases of Blockchain
It is important to understand that majority of use cases you read online today regarding Blockchain are conceptual and theoretical. NFT’s are probably the first feasible use case to come out of blockchain technology. Imagine if you were in 90s during the inception of World Wide Web. You might read someone writing that with the powerful capabilities of a web browser soon people could stream movies over internet. But it took good decade for the software and hardware to mature to support it.
Think of Web3 in a similar vein. The platforms in no way can even remotely replicate what we execute today over Web2.0 ecosystems.
Regarding Advertising on Web3
One often postulated example of blockchain and by extension smart contracts is using it to replace the nebulous ad tech ecosystem. Anyone who has dipped their feet into the world of Adtech know how it is riddled with third parties including DMPs, Ad networks, Ad servers, SSPs, Publishing ecosystems, ad verification platforms, the list goes on. The result is a few people gaming the system leading to challenges like ad frauds by bots, brand safety issues, lack of transparency over pricing and poor inventory.
Considering Blockchain is theoretically decentralised you can streamline the transaction between the advertiser and publisher with limited (important to understand that Blockchain doesn’t eliminate intermediaries) third parties. Considering the clicks are stored in an immutable ledger, the chain could verify on whether the click was legitimate. A third party can verify and probably also add a privacy layer over the ledger (through multiparty computation - MPC) to protect the parties involved. Instead of paying commissions to third party platforms like you do in ad tech ecosystems, you would pay them to the miners who verify your ad transaction (based on proof of work or proof of stake).
But as I said this doesn’t essentially negate the influence of third parties. You would still need companies to write systems that can help you match audiences, or store your creatives.
I would recommend reading
this research paper by IEEE which goes deep into how this can be executed but also highlights some nagging issues that we already see in the crypto industry including the massive electricity consumption, the problems with trust, regulations etc.
There is no need to feel FOMO with the developments in Web3. You can keep an eye on the developments in the space, but be rest assured that as it stands, Web3 offers none of the capabilities of Web 2.0