In simple words – same was Web 2.0 (what we know as internet) but based on decentralized network instead of on big tech companies servers and control.

Web 2.0 can be understood by looking at the companies like Google, Facebook, Flipkart, Uber and so on i.e. it provides advance functionalities to users with data collection and tracking, to the extant that it know more about you and your life than you know yourself. (2 way exchange of information and data)

Web 1.0 was just internet pages which you can search and read, like big Wikipedia. (One way exchange of data)

Key things to know (both good and bad) about Web 3.0 are following but first understand what is Decentralized network.

Decentralized Network – Networks which is not based on one central server or bunch of server of company, the data is stored on 100s and 1000s on computers which are not owned or controlled by one individual or company.

If you look at Ethereum for an example, which is a network on which you can write codes and also use the coins as currency has more than 300,000 computers on which it runs across the world.

Now the key things –

1. No one controls the Web 3.0 i.e. it is run on decentralized networks, so no company and set the rules.
2. You can own your own data i.e. companies like Facebook, Google etc. cannot take your data or track you across internet.
3. Technically network cannot go down because it is based on 100s and 1000s of computers and not one central server.
4. No account or data can be censored because no one company or individual had the control.
5. Currently the speed of the network is not as good as Web 2.0 because the it is not based on central network.
6. Any changes take lot of time to implement because majority needs to approve the change i.e. consensus based.
7. Cannot be hacked, because it almost impossible to hack 100s and 1000s of computers which are not running on same server

and many more, but hopefully this gives you a good understanding of what Web 3.0 is.