A favorite professor, teacher or mentor is not everyone's favorite--we differ when it comes to our preferred style of instructor and guide. Different voices speak to us.
When developing a PLN, it is essential to find the "voices that speak to you." It's also essential to continually try out different "voices" by reading a variety of blogs, watching diverse videos and listening to multiple podcasts. Essentially "adopt" mentors and PLN members by following those that inspire you on Twitter, Linked-In, your professional Facebook, MightyBell, their blogs and more. Engage in #chats like #edchat, #satchat, #4thchat and more that your online mentors engage in.
Also make sure to follow a few whose voices don't "speak to you" as they are the chisels that refine your own voice and challenge your thinking--that's essential.
Finally, take a few minutes now and then to analyze the kinds of people you follow and what they have to say as that will tell a lot about you with regard to your vision, direction and intent.