# Talk:Metcalfe's law

## How you measure that value?

Value can be measured as number of users using the system. But I am not sure whether there is any precise meaning of value in the context of Metcalfe's law.

Perhaps it would be better to explain that the value of a system is a function of the number of users, then describe the nature of that function, without being so specific.

[--anon.]

Are all nodes of value?
Can some nodes even represent negative value?
A negative value node might be defined as being an influence that effectively suppresses the value of interconnectivity by injecting into the network negative interference.
An example on a computer network might be SPAM, virii, Denial of Service attacks, etc. An example on a human level might be the annoying guy on a chat room that "flames" other members so that discussions get no where as members react to what the flamers says (or worse, leave the network).
As more connections are made, the likelihood of a negative node, or nodes, becoming part of the network increases. This would result in an increase in interference and a suppression of value gained from being connected to more nodes on the network.
[--other anon.]
Odlyzko and Tilly themselves address the issue of some nodes in a network which subtract from its value (spammers, etc.) as well as the negative value of being faced with too many choices. They refer to two sources (McAfee and Oliveau 2002, Rohlfs 2001) which make the same observation. Maybe in the paragraph about Odlyzko and Tilly there should be a reference to this point? Perhaps, "Some connections are even of negative value, for example those which result in unwanted calls from telemarketers." [--anonymous]
what would be a formula to convert a network size back to an original number of people (or a close estimate)? [--another anon.]

## Is Metcalf's law a law?

A law is the formulation of a principle that can be applied to all special cases falling under that law. Just because Metcalf, Odlyzko &Tilly as well as Reed have clad their ideas into mathematical formulas they cannot be called laws. They could be called Metcalf's rule, as in "rule of thumb". They are just that: rules of thumb expressing estimated proportions of increase of value dependent on growth. [--yet another anon.]

I asked Metcalfe at [this event] and he expressed what seemed like a pretty sincere displeasure that it was regarded as a proper Law. Moore's law obeys strict empirical math, where's so-called Metcalfe's Law is more about trend fitting moving ratios. He says as much quotably in his [Network World] interview, and a number of other places on the net. On the other hand theres zero chance anyone will ever get the name changed, its probably going to be called Metcalfe's Law forever. A good question might be, where did the name originate? I didnt ask that one.
--Rektide (talk) 06:16, 8 April 2008 (UTC)
Rektide, you seem to know something about this subject. Can you add a section to the article, like "Is it a law?" or "Further studies" or some such heading? I see some titles in the External Links section that suggest disagreement with the "law", but I have not the expertise to do right by them. I will also add "A Group Is Its Own Worst Enemy".
Thnidu (talk) 14:56, 16 April 2008 (UTC)

## Is Metcalf's hypothesis ?

In today's internet era where information travels with the speed of light and the information is shared at the click of a thumb based on a neurons split second decision we can accept it as law based on various evolving proven experiences based on a number of occurances. In my opinion They should and could be called Metcalf's rule, as in "rule of thumb". — Preceding unsigned comment added by Vdhananjay (talkcontribs) 15:57, 16 May 2014 (UTC)

## Economics

Seems to me this ought to be tied into the (micro)economic concepts of strength of networks in general; "If everyone owns an IBM why should I buy Macintosh? I can't trade games or get help from my friends." --Belg4mit 03:56, 7 February 2007 (UTC)

Why? That proposition is a self-evident deadend. If it really meant anything, Apple Computer would have gone under around 1984. I don't think Metcalfe's Law is all 'at, but this particular tie-in doesn't seem all that on-point to me. Or perhaps I'm blatantly missing your point? (Been known to happen from time to time...) — 06:09, 7 February 2007 (UTC)
Yes, you are missing the point... that was just an example statement of the economic principle. However I see that it is linked under see also (I couldn't recall the proper term earlier), and have ammended the text. --Belg4mit 00:56, 8 February 2007 (UTC)
Works for me! — 23:00, 8 February 2007 (UTC)

-- Comment by NormenBenjamin : it is wrong this way. it ignores the differentiation processes which are vital for structural evolution in order to reduce local complexity.

## Why use a 5-point call which yields a Satanic pentagram as an example?

Aren't Christians going to be offended by this article's presentation? 71.131.188.119 16:19, 2 May 2007 (UTC)

Offended? I thought they believed in Satan? Rob cowie 21:43, 2 May 2007 (UTC)
Um, no. There isn't anything intrisically Satanic about five-pointed stars. Otherwise the American flag would be in pretty big trouble, what with 50 of them. — SMcCandlish [talk] [cont] ‹(-¿-)› 06:15, 3 May 2007 (UTC)
The graphs that illustrate this concept are just planar Kn graphs.

## Metcalfe's Law doesn't apply to other things

I removed the entire section "applications of Metcalfe's Law" because none of the examples are applications of the law. Rather, they are proposals of separate laws that use the same mathematical relationship (squaring). Metcalfe specifically theorized about the value of telecommunication networks. His reasoning obviously applies to other things, but the law is not just a name for squaring.

There's a law that says gravitational attraction varies inversely as the square of distance. The same mathematical relationship holds for electrical attraction, but we can't say the law of gravity applies to electrical attraction.

Bryan Henderson 16:18, 12 September 2007 (UTC)

## Transportation

Does Metcalfe's law apply to transportation networks? In some cities, it seems like urban rail systems are a big waste of money. But it also seems like they would be of greater value if they only connected more people. —Preceding unsigned comment added by 71.178.168.179 (talk) 01:39, 6 May 2008 (UTC)

## Is that much math necessary?

I'm surprised at the mathematical derivation in this article; it seems like overkill and I doubt it is helpful to most people looking up the term. I'd recommend just saying something about the number of edges in a network being n*(n-1)/2 and saying that scales like n^2. Actually taking limits in the middle of this article seems too much... anyone who understands limits knows the math here already, and those who don't understand limits will be mystified and may come away believing Metcalfe's law is super-mathematical.

Since I'm new to editing this article I thought I'd bring this up here rather than just deleting a lot of stuff. But if I don't hear objections, I will rewrite to de-math-ify this a bit. --Infografica (talk) 20:00, 8 August 2008 (UTC)

I have now made the changes I proposed a few days ago. I hope the result is simpler and more accurate article! --Infografica (talk) 23:40, 11 August 2008 (UTC)
Hi, I restored the math section. There are a lot of this kind of chapters in math article. The only reason to delete this is if it is wrong.
If you want to delete such kind of things please wait untill other people agree on that. In Wikipedia this can take weeks or months sometimes.
-- Marcel Douwe Dekker (talk) 00:38, 12 August 2008 (UTC)
Hi, Marcel--yes, the equations would be fine if it were a math article. But it's not a math article, or even a science article: that's the point I was trying to make. Metcalfe's law is really a heuristic or metaphor. (Please see the section of this talk page entitled "Is Metcalfe's Law a Law" for some links where Metcalfe himself makes this point.) The reason I deleted the material is that a strict derivation with limits seemed like it didn't add anything, might intimidate some readers, and furthermore might convey a false impression that this was actually a scientific law. But perhaps I was hasty in deleting... I thought waiting a few days after I put this on the talk page meant it was safe to continue. So I'll wait a month or so before doing anything more here, to see if anyone else has opinions. --Infografica (talk) 01:52, 12 August 2008 (UTC)
Ok. You can wait. You can also contact other editors of this article, or remove the section a second time to trigger some more respons here. I even agree with that third opion now. I noticed in the history of this article that more parts have been removed without complains. The current article is a lot less in compare to last year, see here. That makes me wonder if there isn't anything solid to say here. I will leave it wit that. Good luck and go ahead.-- Marcel Douwe Dekker (talk) 07:53, 12 August 2008 (UTC)

## Logistic Map

Metcalfe's Law, reformulated as -1/2*n*(1 - n) is a special case of http://en.wikipedia.org/wiki/Logistic_map

It also pops-up in http://en.wikipedia.org/wiki/Rational_trigonometry during spread calculation — Preceding unsigned comment added by 85.141.136.34 (talk) 01:16, 15 June 2011 (UTC)