Google Shared Stuff was only used to share videos at Google Video and Knol articles, but it was buggy and underdeveloped. Shared Stuff combined different ways to share pages with other people: by email, using social sites like del.icio.us or by adding them to a public page.
As usually, Google's suggestions for replacing the discontinued services are hilarious:
"If you want another way to share videos, you can use the "Share" link below each YouTube video. You can also create a public Google Site if you want to share websites and links with friends."
A more appropriate replacement is Google Reader's sharing bookmarklet, that lets you share content from any web page. There's also AddToAny, which combines multiple sharing options in a crowded page. Many other social sites offer sharing bookmarklets: Facebook, FriendFeed, del.icio.us.
{ Thanks, Jamie. }