It's easy - just select the desired access level, copy this link and send it via email, instant message, etc.Link: Just a link to your wiki. Post this anywhere and people can ask you for the invite key.
Euforic website aggregates del.icio.us (and other?) content of various sources? Example of decentralized content management. Letting the people in your network do the talking!
IAALD weblog and del.icio.us content are provided on the IAALD website
Marshall Kirkpatrick provides a topic specific OPML feed that cobines various resources at once. Example of being a personal filter and help those that don’t know all the ‘best’resources.
Early warning system. (Hugo working on this with IFPRI). Use of content aggregation to notify people (per email/sms/instant messenger) of food security issues. (E.g. locus threats)