You are if you sign in with a “Global ID” such as Facebook, Twitter, etc. from or to other websites.  It’s much easier to do that, but you need to know what you give up in the process to the site you use it with.  Here is a graphic that shows you what you tell about yourself:

[click image for larger size]

According to the infographic provided by Gigya:

Using Facebook as a Global Login ID:

• Across all sites:  46%
• Entertainment Sites:  52%
• News Sites:  25%
• B2B Sites:  37%

Using Twitter as a Global Login ID:

• Across all sites:  14%
• Entertainment Sites:  15%
• News Sites:  45%
• B2B Sites:  18%

Using YAHOO as a Global Login ID:

• Across all sites:  13%
• Entertainment Sites:  11%
• News Sites: 10%
• B2B Sites:  18%

Using MY SPACE as a Global Login ID:

• Across all sites:  7%
• Entertainment Sites:  14%
• News Sites:  1%
• B2B Sites:  3%

Using Linked In as a Global Login ID:

• Across all sites:  2%
• Entertainment Sites:  0%
• News Sites:  1%
• B2B Sites:  3%

AOL and ther IDs reported at 1% or less.

Source: Gigya. See the full infographic.

Understanding Social Media Marketing is as simple as understanding the quality of your online [and offline]  social interactions.

This great infographic will help you define where on the spectrum your friendships are, and help you grow them to the next level.

(Click image for a larger -easier to read view)

Thanks to Mike Auaraz:  http://www.mikearauz.com/images/spectrum_friendship.jpg