GenZedong

Say what you will about capitalists owning the railroads, utilities, etc., I and most people reading this don't work for these companies for free and therefore give these companies egregious valuations.

You probably pay for the bus, internet connection, phone, as well as the imposed value of transportation and infrastructure on your consumer goods, rather than get it for "free" in exchange for some valuable data. And your employer probably also pays that rent in their literal workspace rents, software licenses, security contracts.

And in the odd case your main income comes specifically from these social media corporations as a "content creator", you're still not a serf, you're more like an entertainer or a marketeer.

Historically, serfs are bound to the land, produce collectively for their own consumption and are "taxed in kind" on that produce for the lord, who wields absolute authority over that land, secures it through his own personal militia, and neither party significantly engages in commerce for their social reproduction.

Wage labourers work for a propertied employer for money, which they use to buy their consumption off of the market. The employer can buy and sell more property and the worker is "free" in the sense they can be fired and seek employment somewhere else. In capitalism, the absolute authority over that worker is the state, as well as the "security" force, and not only is the worker expected to rely on commerce for social reproduction, but every single aspect of society (like the aforementioned security) is tendentially reduced to commerce.

I don't see how any rigorous definition of serfdom would define corporations extracting surplus from their property of surveillance systems — as, if extracting your data cost no labour, it'd have no value — as somehow closer to feudal lords than landlords, or their targets as serfs.

It's just monopoly capitalism, A.K.A. imperialism, as it manifests in the core.