I've found these kinds of tools really useful while running http://OfferLetter.io and coming up with a responsive content marketing strategy. If you liked this, you should definitely check out http://notify.ly/ - it works across social media sites and gives you push notifications on a Slack room you specify. It's been wonderful for staying on top of the dialogue!

This is a small internal tool we open-sourced. It handles the main feature from Mention that we were using, without any specific limit on the number of keywords and based on Slack notifications. Hopefully it'll be useful to others as well :)