According to the legend, there was such a plugin. There were some complaints from people, though, regarding a couple of bugs. Maybe they had been fixed. Here is the post: http://www.question2answer.org/qa/31733
It seems the only link to the plugin is this one, as the author has removed the file from his Dropbox: https://github.com/ProThoughts/q2a-hashtagger
Welcome to the Q&A site for Question2Answer.
If you have a question about Q2A, please ask here, in English.
To report a bug, please create a new issue on Github or ask a question here with the bug tag.
If you just want to try Q2A, please use the demo site.
April 20, 2021: Q2A 1.8.6 released!