I have a few on my blog, https://blog.andrewcantino.com, but nothing comprehensive. I mostly use it to monitor Reddit/HN/Twitter/various blogs for certain keywords, and also to keep an eye on local things that I want to know about (weather, events, emergencies, etc.).
It's trivial to write your own agents, and use other 3rd party gems in those agents. For fetching data from LinkedIn, checkout https://github.com/mdesjardins/linkedin-v2 (YMMV)