My default seems to be who-/whatever I posted to last time. Add to collection means "add to collection". Practical example: I share my uncles interest in clean

My default seems to be who-/whatever I posted to last time. Add to collection means "add to collection". Practical example: I share my uncles interest in clean energy solutions but not his taste in music. Unlike twitter, on g+ I can easily follow his collection about clean energy without seing everything he posts.