Via the official Google Blog, word that the Gooogle "+1 button" introduced in March ("recommend content to your friends and contacts directly from Google search results and ads") will now be available to the whole web.
"As a result, you might start seeing +1 appear on sites large and small across the Internet," the introductory post continues.
A bit of internet proto-history: the +1 button dates back before the graphics and media-rich web as we now know it. Exactly when and where did its use online originate? There is some proof that "+1" was used an indicator of approval or recommendation on Usenet and the Apache list back in 1993 (thanks, @waxy). It was also used on IRC, BBSes and Usenet as far back as the mid-'80s, from what I can tell (thanks to all on Twitter who chimed in to the conversation this morning with personal recollections).
A bit of internal BoingBoing sharing: we've used it on internal email threads for as long as I can remember, sometimes to the amusement of newcomers.