[danpalmer]

It sounds like you are coming from the position of "prove to me Twitter does customer support", and you're right I went and gathered some evidence for this. If you started from that position though I think you're entirely justified in not realising this was a customer support interaction.

However, in my experience of ~14 years on Twitter, seeing support processes inside companies, and as a consumer, I think most consumers treat any two-way comms channel from a company as customer support regardless of whether the company is providing it. Many even treat review websites as customer support, despite it being wholly inappropriate for that.

Companies do support on Twitter because their customers are treating it like that, not the other way around.