I'm so bad at carrying a tune, those 'find a song by humming its melody' websites throw an HTTP 406 error as soon as I start to hum.
Services like MusicBrainz and SoundHound can detect a recorded song's acoustic fingerprint and match it with an existing song. This lets them identify the title and artist of an unnamed recorded musical extract. In this comic, Megan hacks the acoustic fingerprint database to add her own entry with a message to Cueball, in which she asks him to buy cat food.
Megan would use this app again in 1199: Silence.
HTTP error code 406 means Not Acceptable. When a client requests data from a server, the client lists the data formats that it can accept. If a server is unable to provide data in any format that the client accepts, the server returns error 406 Not Acceptable. For example, this can occur if a client requests XML but the server supports only JSON. In the title text, the standard meaning of the error message is ignored and the text "Not Acceptable" is taken literally: The server is offended by Randall's humming.