With the #photography tag, questions and discussion can get lost amid all the photos being shared. I've made a few posts using the #PhotographyDiscussion  tag.

Some other potentially useful tags that came up when I did a hashtag search:
#PhotographyTip
#PhotographyGear  
#PhotographyTalk  
#PhotographyAdvice
#PhotographyTheory  
#PhotographyThoughts  
#PhotographyQuestions​