Wikipedia is full of claims that are sourceable in principle, but aren't actually sourced.Mainstream journalists use information from Wikipedia, even if it is not further sourced. (He has an anecdote to illustrate the point.)Those very articles can be viewed as authoritative for Wikipedia's own sourcing purposes.Thus, unsourced information could, by virtue of having been placed in Wikipedia, grow to be regarded as authoritative by Wikipedia itself.

30 Boxes lets you connect with the people who matter most.
   
Remember Birthdays
 
Know What's Going On
   
Get Stuff Done
   
Keep Up With Friends
   
Painless Organization / Sharing

critically acclaimed calendar, natural language entry, ajax, full screen, blazing fast, invitations, sms reminders, repeating events, integrated maps, tagging, share by tags, customizable, multiple themes, simple sharing, weather, track myspace, flickr, webshots, livejournal, blogger and more, instant photo sharing, your calendar is a timeline, add rss + ical feeds, all data is exportable, calendar badges + widgets, instant home page, track your buddies, custom webtop/start page, reliable messaging, tracked link sharing, the best to do list ever, perfect for GTD, buddy cards, great for your contact list, sms messaging built in, available on your phone, status updates, better than paper!