I have a living Satguru, with whom I can communicate at any time, person to person, via email, or in Real time if circumstances happen. In this tradition, a living Satguru is necessary, and the highest knowledge is passed orally in person one to one.
Before Satguru Bodhinatha Veylanswami, his predecessor, Satguru Sivaya Subramuniyswami was my Guru. I first met Him in 1974, so it's been 46 years this summer. It's a practice based, sadhana based tradition, Naninatha sampradaya, of monistic Saiva Siddhantha.
There has been no other influence, at least not in any strong way. We practice 'loyalty to the lineage' that means once you've found what you're looking for, you stick with it. (like a marriage ... one life, one wife) There are many others with many different living Gurus who practice it this way as well. It's rarely mass market, and often purposely restricted through various means (not advertising, for example) . Quality over quantity. (A large 'flock' would mean less care for each.) So many folks filter through these types of sampradayas, but many move on as well. There is no compulsion, but you definitely have to demonstrate commitment.