Lately, I've been using Google Plus as a way to find, collect and create content. Here's what I've been doing (I'd love to hear your thoughts).
The search features in Google Plus are extremely robust. You can search public posts, posted shared with you, Personal Profiles (the parts that are public or shared with you), Pages and Sparks.
You can even use Google's Search Operators when searching Google Plus. This allows you to fine tune the results and save time.
When you do a search on Google Plus, you can also save the search in your left-hand sidebar (under "What's Hot").
A very common way to use Circles is to categorize people you follow based on their area of expertise. I have a circle that includes nonprofit techies, where I've discovered useful articles, ideas, and discussions.
What makes using circle different from using search is that circles allow for off-topic discoveries that could never happen with "pre-meditated" searches.
When we think of Google Circles, we normally view them as a tool to organize people. But why not create circles for storing content that you've discovered on Google Plus?You can do this by creating a circle, and adding only you to this circle. When you do this, anything that you share with this circle will only be seen by you (this stream is located under your profile image with all of your other circle streams).
When you create a private circle as described in the previous bullet point, you can add notes, links and even draft out ideas for your content piece. Remember that no one can see any of this because you've shared the circle with yourself (you also don't need to lock the post).