Still wondering whether it was unsuccessful as a product or as a concept.

Can we even distinguish those in practice? AFAICT its main problem was being so general-purpose that it was hard to describe as a compelling use case.

Of course, I also don't subscribe to the belief that the popularity or memetic prowess of an idea defines its "success" except commercially. I thought it was a very nifty thing. To me, that counts as a success. Alas, that is not the metric used by companies. :p