Tableau was spun out of Stanford in 2003, from project Polaris, led by professor Pat Hanrahan and Chris Stolte. It was originated at Stanford as a government-sponsored (DoD) research project to investigate new ways for users to interact (including VizQL) with relational and OLAP databases. In 2004 Tableau got $5M from VCs. In 2005, Hyperion (now Oracle owns Hyperion) began to offer a Tableau under the name “Hyperion Visual Explorer“. Currently Tableau has 4 products: Tableau Desktop ($2000 for Pro edition), Tableau Server ($10000 for 10 users), Tableau (free) Reader and Tableau (free web service) Public. In 2010 Tableau had about $40M revenue and was one of the fastest growing software companies in the world (123% YoY). Tableau 6 able to read from almost any data source, including SSAS OLAP cubes and PowerPivot. This is an article (published in 2010) comparing Tableau with PowerPivot.
Tableau established a partnership with Aster Data in 2010 and a few months later (on 3/3/11) Teradata bought Aster Data – I think it will create some interesting opportunities for Tableau. Tableau community is very active on LinkedIn and when I recently published a poll about DV tools, they voted more actively in favor of Tableau compare with supporters of other tools: http://linkd.in/f5SRw9 . Eventually Tableau ended-up sharing 2nd and 3rd place with Qlikview (23% of votes each) on this poll. Also Tableau can read (in addition to Aster Data nCluster) the Teradata as Data Source, see it here: http://www.tableausoftware.com/new-features/6.0 . Since traditional BI is not growing as fast as Data Visualization sector of it and Tableau is a fastest growing company in BI and Data Visualization business, it will be natural for Teradata to unite with Tableau one way or another.