I began in January of 2012 with my personal page, and then I created some business pages. I'm really not selling anything, I was just doing this to find out how it all works. The pages I created were for my cartoons, my garden, and historical images of Phoenix. After a while I got rid of the gardening page (I already have a blog for that) and the cartoon page (I already have a website for that), but I have kept up with the Phoenix Historical Images page. In fact, in the past year I've done over 4,000 posts. And yes, they're all there, and yes, Google has indexed them so they can be found by people who search in Google. And if you want to find your old Google+ posts, this is the best way I've found so far:
Remember that Google+ is based on Google's Search Engine. If you just scroll through things, you're missing one of the best things about Google+, and in my opinion, the internet itself.
In Google+, search for some of the keywords of the post you're looking for. To help refine the search, select "From You" (which is a pulldown menu). You may not be the only one who posted about Gill and Wharton Real Estate!
If you haven't used this in Google+, you are missing out on one of its best features. Google+ is not about inane chatter, it's got some really cool people posting really great stuff.