The way people can find content on social media is by using #'s (hashtags). I know this is not a dot com but I have the following .biz domain name for sale with the exact key word that your viewers can associate with.
What do you think a viewer will immediately associate with the blog or tool Hashtags.biz? Look at HashTags.org. Great tool! You can do the same.
I know .biz is a concern, what other concerns do you have about the domain name Hashtags.biz?