Because of its social media component, Steem has sometimes been compared with the alpha-dog of social media, none other than Facebook itself.
Well, let's be honest, it's unlikely Steem will reach a user base of over 1.5 billion. Even if Facebook will be on decline in its user base, overpassing them in this area is unrealistic.
There are other more realistic targets that have been stated, like Reddit.
Facebook has on its side the first mover advantage in the social media, a huge user base we have already mentioned, a site and business developed in years, almost infinite funding compared to competitors. Pretty much everyone and everything with internet access has a Facebook page or group.
At the same time, it is centralized, also has censorship, as well as increasing numbers of unhappy users, especially savvy ones, who understand their business model. As a company, Facebook Inc. also owns Instagram, you will see why this matters.
Steem on the other hand is not an application, a website, an interface, but an entire ecosystem. It provides the censorship-free blockchain layer on which numerous decentralized applications are built (including Busy - more toward a combination of blogging & social media type, and Snapshot - Instagram like (see?); but let's not forget the awesome DTube and DLive and many many others), it provides a working reward system for anyone on the Steem blockchain to use, it provides a stable governance model and a working and used "product".
Countless decentralized applications (Dapps) and tools plug into the Steem blockchain without paying any fees (other than for running their own servers, if they need them) and make the ecosystem grow every day, alongside its user base. Users can earn rewards daily through blogging and other means which are becoming available to them in a larger variety as time goes by and they are being developed.
And that's only the beginning, now before the Smart Media Tokens are out. From March next year, Dapps will be able to create their own tokens, have their own ICOs, all lying on the foundation of the Steem blockchain.
Now tell me how could Facebook do all that? I've read they are looking into blockchains. Good luck! If they will have their own crypto, it would actually be great for the mass adoption of the entire crypto sphere, but Facebook itself will never be decentralized and running on a public blockchain. That would mean losing control, and that's all they care about, besides profit.
I don't see how Facebook Inc. could develop a structure on which to run all of their websites (including Facebook.com and Instagram.com), add a rewarding system as well, and allow others to do the same on their structure. If you want to go one step further, imagine how would they allow it for free as Steem does! That's impossible!
Blockchain, and Steem in particular, is years ahead of an old-fashioned social media environment like the one Facebook provides. And Steem is now, but mostly will be much more than a blogging and a social media platform.