Because (some) people are less interested in "microblogging" than "twitter as a platform". Pownce didn't have a useful API. At least not one that I ever found

Because (some) people are less interested in "microblogging" than "twitter as a platform". Pownce didn't have a useful API. At least not one that I ever found a use for... And because people thought of it as a Twitter competitor (yes, I realize I just did this above), where it was more of a Tumblr competitor with a worse interface, ads, and paid subscriptions.