I'm currently using a least-squares linear regression model trained with n-gram (unigrams) feature hashing, based on various social media metrics, with a heavy weight on sharing. It spits out a number between 1-50, with 25 being the most common.
Pretty much everything is automated with Huginn[0]: web scraping, data formatting, interaction with Azure ML[1], all of which is fed into a wordpress install using the pluginhunt[2] theme.
Let me know what you think!
[0]: https://github.com/huginn/huginn [1]: https://studio.azureml.net/ [2]: https://epicthemes.com/product/plugin-hunt-theme/