Younger viewers may wonder why a typewriter keyboard has @ on it*. Surely typewriters predate electronic email and even social media where the @ is in very common use? Well indeed that is true they do, despite this typewriters have included @ since the late 19th century almost universally. This is because the @ symbol has another important use which predates computer communications by many decades.
@ is an abbreviation for "at a rate of". As we saw earlier in this series (the fractions episode especially), typewriters in their heyday were working machines not something poseurs and hipsters fart around with using them for nonsense (such as creating blogs about them). One major real use for typewriters was to create and fill in forms and invoices and other business communications. Here the @ symbol was very useful indeed. One example might be an invoice where you would list the cost of a widget such as "5 widgets @ £10 each". Nowadays of course typewriters can also type someone's social media handle...
* This post is inspired by a question on Stackexchange asking why typewriters have the @!
