Open Letter: Dear C3.js & the community from billboard.js

Dear @kt3k, @masayuki0812 and C3.js community:

The year 2021, [billboard.js](https://github.com/naver/billboard.js) project turns its 4yrs of journey after the [initial fork](https://github.com/naver/billboard.js/tree/1.0.0) from C3.js v0.4.11 Jun, 2017.

The initial motivation and reason of the new project were arose from the doubt of the continuity of C3.js.

> [Why we decided to start billboard.js?](https://github.com/naver/billboard.js/wiki/Why-we-decided-to-start-billboard.js%3F)

C3.js has been contributed and helped facilitating the ease way to visualize data on the web, and it should be respected for the works done.

How to make these efforts done continues without the worries and concerns of the discontinuity?

The big and hard part of the Open Source project faces, are the "sustainability" and the "imbalance" between producers and consumers.

How to solve them? How to make worth OSS project continue its way?

We're not writing to give or propose any solution, but we're strongly believe with the help & contribution from the community can over come(or at least make better) this.

From the billboard.js project, we showed and proved the willing and demonstrated its stable continuity of the project by adding & enhancing the functionalities such as:

- New chart types
- [Radar](https://naver.github.io/billboard.js/demo/#Chart.RadarChart), [Area range](https://naver.github.io/billboard.js/demo/#Chart.AreaRangeChart), [Bubble](https://naver.github.io/billboard.js/demo/#Chart.BubbleChart), [Muti Gauge](https://naver.github.io/billboard.js/demo/#GaugeChartOptions.GaugeTypeMulti)
- Introduced [Plugin Interface](https://github.com/naver/billboard.js/wiki/Plugin-Interface) & its plugins
- [Bubble Compare](https://naver.github.io/billboard.js/demo/#Plugins.BubbleCompare)
- [Stanford Diagram](https://naver.github.io/billboard.js/demo/#Plugins.StanfordDiagram)
- [Text Overlap](https://naver.github.io/billboard.js/demo/#Plugins.TextOverlap)
- [Performance improvements](https://github.com/naver/billboard.js/wiki/CHANGELOG-v2#reduced-node-generation)
- [billboard.js 2.1.0 release: Another big step for performance improvement & more!](https://netil.medium.com/billboard-js-2-1-0-release-another-big-step-for-performance-improvement-more-9f0b9357d9d5)
- [Make able to be tree-shaken](https://github.com/naver/billboard.js/wiki/CHANGELOG-v2#modularization-by-its-functionality) to cut down final bundle size
- [Themes](https://github.com/naver/billboard.js/wiki/Themes)
- Ensured the stability by increasing the [Test Coverage up to 90%](https://coveralls.io/github/naver/billboard.js)
- Transition of codebase to TypeScript
- Various new enhancements options
- Pie's [inner](https://naver.github.io/billboard.js/demo/#PieChartOptions.InnerRadius)/[outerRadius](https://naver.github.io/billboard.js/demo/#PieChartOptions.OuterRadius), [Multi Axes](https://naver.github.io/billboard.js/demo/#Axis.MultiAxes), [Legend Template](https://naver.github.io/billboard.js/demo/#Legend.LegendTemplate1), [Custom Data Points](https://naver.github.io/billboard.js/demo/#Point.CombinationPoints), etc.

TBH, we don't know the current status of the C3.js project and its continuity, but as we expressed the worries as 2017,

> If this status continues, as your worries and concerns, is quite reasonable to predict the death of the project.
> https://github.com/c3js/c3/issues/1965#issuecomment-280543868

it seems similar concerns are expressed by the users again. (correct us if is wrong)

> - [Dead ?](https://github.com/c3js/c3/issues/2822)
> - [C3 HAS BEEN FORKED BY BILLBOARD.JS WHICH IS ACTIVELY MAINTAINED](https://github.com/c3js/c3/issues/2829)

Very carefully, we want to propose the idea of **"unifying the efforts"** (like inviting all core committers, etc.) to billboard.js.

Providing an unified source, surely will make beneficial to all.
And will make stronger the legacy and its works done from the C3.js.

Hopefully the proposal idea to be understood in a good way and to be considered positively.
(Also welcoming any other improved ideas/opinions as well)

Sincerely,
from the billboard.js team.