Noble Friendship (Kalyana Mitta) in modern times

Noble Friendship is to be understood as association with those who influence the practise of the Noble Eightfold Path (SN 45.2). Noble friends are those teaching the True Teaching (AN 10.61). For example, those desperately & frantically trying to promote belief in reincarnation, Brahmanistic gods & heavens & other superstitions are not actually noble friends because they are leading away from the perception of impermanence, unsatisfactoriness & not-self required for the Noble Path. In the 1st sermon, the Noble Realisation of the Noble Truths leading to Noble Stream-Entry was: "all subject to arising is subject to cessation". It was not "all subject to cessation is subject to re-arising". MN 117 makes it unambiguously clear there are two sorts of dhamma: (i) defiled self-view dharma, which sides with only morality; and (ii) Noble Dhamma, which is a factor of the Noble Path. SN 45.2 (below) says unambiguously the Noble Friend guides to the Noble Path:

Don't say that, Ananda. Don't say that. Admirable friendship, admirable companionship, admirable camaraderie is actually the whole of the holy life. When a monk has admirable people as friends, companions, & comrades, he can be expected to develop & pursue the noble eightfold path.

Upaddha Sutta: Half (of the Holy Life)

Kalyāṇa is a word translated as "beautiful, charming; auspicious, helpful, morally good", by the way -- not the same word as ariya (which is the word that's usually translated as "noble").

Kalyāṇa is used in lots of other contexts, mostly not to do with "friends" (i.e. where the adjective qualifies a noun other than "friend" or "friendship") -- e.g. in the first search result from that list (AN 10.47), it's an adjective used to describe "good deeds":

What is the cause, sir, what is the reason for doing good deeds, for performing good deeds?”
“Ko pana, bhante, hetu ko paccayo kalyāṇassa kammassa kiriyāya kalyāṇassa kammassa pavattiyā”ti?

So what does the adjective mean when it's ascribed to, when it describes, friend and friendship? That's explained in three ways:

1. What are the qualities of a good friend (what do they 'have')?
2. What is the function of a good friend (what do they 'do' for you)?
3. What is the effect of a good friend?

Piya Tan wrote a translation of the Upaḍḍha Sutta with some analysis in its introduction. Several paragraphs of that introduction include the phrase, "According to the Sutta Commentary" (so I think that his introduction is based on or inline with that commentary).

1. "What they have?" appears to be these qualities:

   1. The accomplishment of faith (saddhā,sampadā),
   2. The accomplishment of moral virtue (sīla,sampadā),
   3. The accomplishment of charity (cāga,sampadā),
   4. The accomplishment of wisdom (paññā,sampadā)

2. "What they do?" appears to be this (I think it's this bit of Piya Tan's introduction that's most worth quoting, because it's the most definitive):

   Spiritual friendship, in other words, is the effecting of the three trainings (ti,sikkhā), that is, in moral virtue, mental concentration, and wisdom. On the moral level, the mentor as spiritual friend serves as a virtuous exemplar. On the mental level, he is a teacher who gives a meditation subject to the pupil, and further inspires and nurtures his meditation and mental cultivation. And on the spiritual level, the mentor motivates his mentee to aspire towards spiritual liberation in this life itself. Spiritual friendship is the mutual rejoicing of both the teacher and this pupil in the Dharma as well as in the goals that such a friendship entails, namely, awakening.

   Spiritual friendship is the whole of the holy life in the sense that the “holy life” (brahma,cariya) is basically our training in moral virtue, that is, the taming and refining of our bodily actions and our speech, or what we do and how we communicate with others. This is the “external” or social aspect of our spiritual training, so called because our moral training, in an important way, is how wholesomely we relate with others in keeping with at least the five precepts.

   Spiritual friendship as moral training is the basis of our mental training, where our spiritual friend is our mentor in mental cultivation. In either case, there is a vital level of instruction from the spiritual friend and wholesome communication between mentor and mentee. This instruction is sometimes known as “the voice of others” (parato ghosa), that is, the beneficial instructions and inspiration from the spiritual friend. The Anguttara Commentary explains parato ghosa in the context of giving rise to right view as that of “hearing the true Dharma” (saddhamma,savana) (AA 2:157).

   “The voice of another” is one of two ways in which right view arises; the other way is the personal effort of wise attention (yoniso manasi,kāra). “Wise attention” here is the mindfulness that is the basis of proper mental cultivation leading to mental focus and wisdom. Our wise attention is fortified through spiritual friendship by way of an inspiring and experienced guide.

   Moral virtue is our wholesome relationship or interbeing with others, which in turn is also the wholesome conditions that nurture our mental cultivation and wisdom (the other two trainings). Moral virtue is always present in the arhat. When we are still worldlings, moral virtue is a catalyst to our spiritual development, and when we become noble disciples, as awakened beings, moral virtue comes naturally to us. We are then spiritual friends to those who are less developed than we are. Hence, spiritual friendship is the whole of the holy life.

3. "What's their effect?" is (explained simply as being) your development of the noble eightfold path.

In summary (my own summary):

• It's not just "wise" people, it's "good" people.
• IDK to what extent you can learn morality via the internet ...
• I think that people do correspond with their mentors -- e.g., in pre-internet times, by writing letters.

• I think Buddhism is a.kk.a. Dhamma-vinaya ...

  Dhamma-vinaya [dhamma-vinaya]: "doctrine (Dhamma) and discipline (Vinaya)." The Buddha's own name for the religion he founded.

  ... the "vinaya" being a.k.a. the monastic code (rules of conduct etc.). That's what I think of and IMO it's to miss something important (including presence, personal example, discipline) if you take the phrase (kalayanamitta) out of (that) context.