Facebook's News Feed model was trained daily in 2018. (Source: https://research.fb.com/wp-content/uploads/2017/12/hpca-2018-facebook.pdf https://research.fb.com

Facebook's News Feed model was trained daily in 2018. (Source: https://research.fb.com/wp-content/uploads/2017/12/hpca-2018-facebook.pdf https://research.fb.com/wp-content/uploads/2017/12/hpca-2018.... If you know of update please let us know.) "requiring constant retraining" is pretty accurate in this case. Facebook trained image understanding CNN ("Lumos" in the paper) only once in many months, but this is not usual.