To sign in to your Lytro account, which will let you share pictures from Lytro Desktop to Lytro Web and/or directly to Facebook, click "SIgn In" in the upper right of your Lytro Desktop screen.
Then enter the email address and password you used when you purchased your camera.
You are also welcome to use the "Login with your Facebook account" option on the left. (This is entirely optional.)
NOTES:
If you have forgotten your Lytro account password, click here.
If you need your own Lytro account-- for instance, if you received your camera as a gift, or share it with others-- then click the blue "Sign Up" text in the upper right of the Lytro Desktop "Sign In" screen, as shown above, then follow the prompts:
IMPORTANT: You must enter your First Name AND your Last Name in the "Name" field.
TIP: For information about Lytro Desktop features and controls, click here.