Ask HN: Sharable Stock Charts Platform?

One of the things I have noticed on twitter is how well it works as a method of sharing information regarding stocks and your sentiments/positions towards a particular equity or option. Obviously Chart.ly and StockTwits have the "stock niche" cornered, except...

Taking a leap of faith based on the guys I follow, most traders who use twitter would consider themselves "chartists" or "technicians", and the ability to share charts is essential to showing their sentiment on a trade. Currently, the only real way to do this is by taking a screenshot of your charting application (or saving a chart at StockCharts.com) and sharing it via chart.ly.

My idea is for a charting / sharing package that would leverage web technologies like JS/HTML (canvas) to create a charting platform much like StockCharts.net, except that it allows users to annotate / mark up / add technical indicators and share that chart (not an image, which allows it to continue updating and be manipulated by other users (think zooming in)). Also, allow for embeding, etc.

Does anyone know of a service like this? What are your thoughts?