Alexa is an artificially intelligent, digital, personal assistant. It was developed by Amazon, and made popular by the Amazon Echo. Alexa, as a product, made its first appearance in the Season Twenty-One premiere episode, "White People Renovating Houses".
It briefly became very popular in South Park, being present in the homes of several familiar citizens. It was later protested against by the rednecks wielding confederate flags, believing digital assistants like Alexa were stealing jobs from them. The protesting worked in the rednecks' favor, and soon, they replaced all digital assistants in South Park, including all Alexa's.