Ask HN: projects for self made web based analytics?

Hi

I am looking for any open source project that gives users a good range of options to make their own analysis of structured data (sales, fiancials, etc.). Sort of like excel, but web based and able to connect to databases to pull data. Mostly I am thinking of giving users the tools to make web based plots, tables, pivot tables, with data from multiple sources (OLAP, external data, submitted data from foreign entities, etc.).

If there is not, I was thinking to start building it. I also was wondering if there is some market potential in this concept.