I don't know what Tableau Software is and I found it pretty amazing that when I Google it I could still not figure it out because all the results were about the stock price. I think people might be focusing too much on stock price is Googling a company's name doesn't result in seeing the company's website on the first page of results.....
Some clever stuff they had was (early-RoR-style) guessing of data semantics based on heuristics (Column labeled "date"? probably worth grouping by months. Number pairs like -0.3242,0.12345 ? probably worth plotting on a map).
I have used trial and educational versions in the past and was always pretty impressed with the ease of use and the results. The product itself was > $1k so I never actually purchased a license.
Even though I didn't follow the strategy very closely, from what I've run into it seems lke their offerings were all over the place. I saw a local newspaper using a hosted Tableau product to display data visualizations on their pages (the kind of visualizations made by a company whose DNA is desktop apps, so kind of underwhelming). Their website is all about Gartner and enterprisey lingo.
The product itself is, well, some advanced version of Excel. This means you either sell a lot of it very cheap, or very little of it for a lot of money. Website design suggests the latter. Too bad it seems to not be working.
I'm honestly sad to see them do badly as I think the product was really innovative and it really changed my way of thinking about report building and analytics tools.