> Based on what criterion?

This is obviously subjective, but based on the criterion that the sites don't work very well. Recommendation systems on all of these platforms are abysmal, and they don't seem to be improving -- they seem to be getting worse. Most changes being made on sites like Twitter are poorly received by users. When the last time there was a change on Twitter that everyone liked?

Most of these sites are slow. Gmail is actively getting slower over time, to the point where it now has an extra loading screen. It's not clear to me what features have been added to justify that.

On sites like Youtube, creators are now at the point where they view the website like an existential threat. Youtube provides almost no real mechanisms for creators to fight copyright claims, its monetization rules and promotion algorithms are opaque and difficult to navigate.

Again, it's subjective whether you should look at that kind of stuff and say, "well no one could do it better." I look at platforms like Mastodon and say, "well, clearly some people are doing stuff like moderation and open API access better than sites like Twitter/Facebook." I look at sites like Nitter and think, "well, if one person built this, and even as just a blind proxy it seems to work better than Twitter's site in multiple ways, then Twitter isn't trying very hard."

> Can you give any examples of anticompetitive behavior exhibited by social media companies?

On Facebook: the email dump that came out late 2019[0] is a good place to start. In it, you can see Facebook design "open" data APIs where access was restricted to partners who spent certain amounts of money on ads. Companies that were considered competitive with Facebook's offerings were excluded from that already problematic agreement. If Facebook saw you as a potential threat, you were essentially banned from the platform.

On Instagram: users were threatened with loss of status and verification if they linked to other platforms in their bios[1]. Eventually, the code was changed to detect "add me" links and outright block them from being included on bios at all. This is a very bold, open attempt to hold a userbase hostage, counting on the fact that Instagram/WhatsApp users have too much to lose to go against the policy.

I know you specifically asked about social media, but if I can broaden that out a tiny bit: on Google's front, Chrome is advertised prominently in every one of Google's products, for free. Google offerings are also built to work best in Chrome even to the point of breaking standards[2].

This kind of "by default" push for Chrome on Android devices and in Google products is, in my mind, very reminiscent of the IE antitrust case the Microsoft got slammed with.

We could go on, but I don't want this to get too long. But it really shouldn't be difficult for you to imagine why someone might claim tech giants are anticompetitive, even if you disagree with those reasons. Heck, a new accusation gets posted to HN at least once a week -- just look at the conversations around AMP's search-result placement.

> If the "original" twitter kept the twitter brand and domain, absolutely nothing would change since that would be the equivalent of the status quo.

Based on Facebook's reactions to Instagram, Snapchat, and other similar competitors, this isn't the case. Every time Facebook has felt threatened by a competitor, in the brief period before they bought them, they were forced to uptake user-friendly features. In regards to Snapchat, some of those features were more privacy-friendly than what Facebook was currently offering.

A better argument that I'd be more sympathetic to here would be that Facebook already regularly feels the pressure of competition, and breaking them up isn't necessary. But it seems strange to me to argue that competition wouldn't do anything at all, given that we have a lot of examples of competition making these platforms better.

> Right, but those products exist because they serve a niche in the market, simply breaking up companies doesn't create a niche.

No, but simply having an unserved niche in the market also doesn't mean a product will fill it. That's what people are getting at, that there are niches that would be filled by competing OSes and products if there weren't anticompetetive forces keeping those products from existing.

You need two things for a niche product to exist -- you need a real niche that's unmet, and you need an opportunity to create that product. Proponents of breaking up big-tech argue that we have the first, and not the second.

Once again, I think there is a case to be made that the situation isn't as bad as people say -- that we do have competitors starting to pop up for Facebook/Twitter, and talk about forcing the market is unnecessary right now. I'm not going to get into that argument, but I don't think the people who make it are dumb.

> Would Valve be allowed to sell 1st party software on Steam? Would Google be allowed to sell their software on the play store?

Roughly speaking, that's the intent. Google would be able to sell software on the Play store, but then Google couldn't own the Play store, it would need to be spun out into another company.

Similar rules have been proposed for media companies and ISPs; people argue that a company like T-Mobile shouldn't be able to simultaneously operate an Internet service and merge with a media provider on that service -- that would create a conflict of interest that would threaten Net Neutrality.

This sounds extreme on the software front because we have a pretty long history of companies doing exactly that -- creating a search engine and then using it to promote Chrome, creating a Play store and then using it to make sure that Gmail has prominent placement. People like Warren argue this is just as anticompetitive as an ISP operating a streaming service.

[0]: https://www.forbes.com/sites/parmyolson/2018/12/05/email-dum...

[1]: https://www.theverge.com/2016/3/3/11157124/instagram-blocks-...

[2]: https://www.cnet.com/news/mozilla-exec-says-google-slowed-yo...