see this screenshot:
http://4.bp.blogspot.com/-B7kh-JD5Uvo/TgoJIYaKCrI/AAAAAAAAVj8/cseuMk10WhA/s400/takeout.png

it is from that posting about Google Takeout:

http://dataliberation.blogspot.com/2011/06/data-liberation-front-delivers-google.html

and it is really in Google Takeout but there is no data in it currently

<< About the stream
The stream is the place to have meaningful conversations with the people you care about. It centralizes all the content people have shared with you, as well as the people who are trying to share with you, but who aren't yet in your circles. You might see text posts, pictures, videos, links, or location markers. When you share with people either individually or through a circle, your content will appear in their stream. >>

http://www.google.com/support/+/bin/static.py?hl=en&page=guide.cs&guide=1257360&rd=1

<< Google Takeout allows you to download a copy of your data stored within Google products. >>

http://www.google.com/takeout

Let's hang out in the stream in the cloud.

x.x

Stream is the data from Google Plus.

Also see the same icon: http://www.websonic.nl/nieuws/wp-content/uploads/2011/06/google_iconen.jpg