I don't recall seeing this on Google+ previously, but automatic recognition with best guess suggestions was certainly a feature added to Picasa Web Albums at so

I don't recall seeing this on Google+ previously, but automatic recognition with best guess suggestions was certainly a feature added to Picasa Web Albums at some point about 2-ish years ago and I know Google+'s photo system is basically a different front-end to Picasa, so you're at least partially right.