Publishing content to a website owned by a traditional social media company means that you have few rights over how the content is monetized or censored. Moreover, your login credentials are stored on their central database. You have to trust that these companies will be able to keep your private data safe, and we have already seen many of the largest Web2 companies (including Facebook and Twitter) suffer from data breaches and leaks. To top it off, there is no way to verify that they are not selling your data.
The technologies powering the new paradigms of Web3 allow users to retain ownership of their own data. Rather than publishing content to a platform owned by a social media giant, you are now given the ability to own, publicize, and monetize your content, which can be fully independent of trusted third parties. Additionally, your login credentials are stored locally on your devices, rather than in a centralized database.