The most important part of an information system is not what features it has, it is who uses the system. Wherever your network of people and information resides, that is where you must be to operate effectively.
The World Wide Web is an information system. The world participates and search engines like google make it useful. It'd be technically simple to create an all new WWW and use a different port and protocol, but futilely ignorant. The world uses the WWW. Join the system or be irrelevant.
Wikipedia.org is effective because that is the wiki that the world updates. There must be millions of other public wikis, but they don't work as well as wikipedia...because the people use wikipedia. It is an information system all its own. Join the system or be irrelevant to it.
Digg, Delicious, and reddit are information systems for labelling and sharing information on the Internet. These systems can be useful when that is where the people and information reside. Same with myspace,facebook,live spaces,xanga, and tons of others. Which tools will eventually win over the people? Those will be the ones with relevance.
How many information systems exist within your organization? How do you migrate people from one system to another? Every system has it's strengths and weaknesses, so 100% buy in is impossible when you suggest any "upgrade." The result is a splintered mess of information systems which do not work. The solution is seldom technical. The solution lies with the people.