A showstopper issue with trying to replace anything with frequent small updates (especially Discord, Reddit, and Twitter) using web3 is simply scalability. ​ Unless a centralized database with decentralized user authentication (web3 wallets) would qualify, there arn't any decentralized databases that would be able to handle the load in the foreseeable future.

Other great apps like Discord are Mumble, Telegram, Tox and Slack, you choose which you use. Have fun Exploring and learning.

I don't think that we will find a replacement quickly for Web2 Social media platforms. I think those Web2 platforms will adjust to the Web3 reality. We can already see this with Reddit implementing NFTs, Twitter giving a possibility to show your PFPs, Instagram and Facebook playing around with NFTs on the Polygon network, etc. ​ I also strongly believe that LinkedIn is going to play an important role in Web3. We can already see this happening with many Content Creators creating on this platform. ​ You can also check a list of the most active ones here on the Airtable: https://airtable.com/shrPIbJqeJDiTvBN3