One of them is the niggling question of security. We have to learn from the Internet experience and ensure this time around users trust the technology. That just might be the ticket to get through the trust barrier. Probably the biggest inhibitor to PKI implementation and acceptance has been the lack of PKI enabled applications. It could be likened to laying thousands of miles of railway track and then finding that you have no trains and carriages to go on it.
Consumers have to be assured that they are transacting in a secure environment.
However, one has to consider that in our fast-forward lifestyle, convenience and ease of use are paramount for any technology to take off and be commercially viable. People are turned on with services and products that would make their lives a lot easier and that is one fundamental key to success. Sure, there is a need for security but one has to bear in mind that users aren't prospective hackers and it does not make commercial sense to install prohibiting Fort Knox-like security. This is not a new stumbling block, and will not go away. For the last 20 years, at least, businesses have been concerned as to whether or not investment in one particular vendor's systems will allow them to communicate and interact with installed and planned systems from other vendors.