From Steve Rosenbaum:
Google’s terms and conditions, buried in tiny print that most users will miss, gives them the right to take control of your content.
“By submitting, posting or displaying the content you give Google a perpetual, irrevocable, worldwide, royalty-free, and non-exclusive license to reproduce, adapt, modify, translate, publish, publicly perform, publicly display and distribute any Content which you submit, post or display on or through, the Services. You agree that this license includes a right for Google to make such Content available to other companies, organizations or individuals with whom Google has relationships for the provision of syndicated services, and to use such Content in connection with the provision of those services.”
The key terms here are Perpetual, Royalty-Free - and most disturbingly - Adapt and Modify.
This means that if you’ve taken pictures of a sunset, or fireworks, or your children playing with a toy - or anything - Google has the right to grab those images, edit them, publishing them, and re-sell them.
If you think the answer is simply that you won’t put any pictures on your G+ page, think again. Google REQUIRES you to link your Picasa account to your G+ account, and therefore requires you to license your Picasa to them under their Royalty-Free contract.