Recommendations needed for a tool to generate leads

Hello,
I have a project that solves the problem of user session management (in the most secure way) that I would like to promote. According to me, the best way to do this is to find people who are facing this problem and then to have a conversation with them about this topic and about my solution - i've noticed that a single conversation is good enough for people to be sold on my solution.

So does anyone know any tool out there that can help me find new posts on various sites like Twitter, reddit, here, facebook groups, linkedin, stack overflow etc.. about this topic? Ideally, I could enter key phrases which the service would use to identify relevant posts and then alert me via email whenever a post is created (a few hours/days delay is fine with me).

PS: if there is no tool like this, I may consider building a basic version for myself.. would you be interested in using this for your needs?

Thanks!