Artifakt Digital

The artifakt Hashtag Plugin allows you to easily and quickly make keywords 
searchable across your website, in the same way it does on other websites where 
hashtags are used. Just adding the # symbol in front of a word or phrase makes 
it a link to the archive page of that hashtag.
Originally this plugin simply created links to a search results page for the 
hashtags, and that worked well but we got to thinking about SEO and how it 
would be nice to index the hashtags on your site. So we created a custom taxonomy 
“Hashtags” (duh) so now you have some options on how you display the archive 
pages and the SEO meta for the pages (if you are so inclinded). You could even 
create a tag cloud of all your hashtags using WordPress’ tag cloud widget.
We are leaving all the customizing of the archive pages and SEO work up to you 
and your theme but your options are much more plentyful since version 2.0
Have fun! And as always, please let us know if there are any issues or 
features you’d like to see.

The artifakt Hashtag Plugin

This plugin makes #hashtagged keywords searchable across your website.

Lorna Timbah

Tag My Hash (#TagMyHash) is a lightweight WordPress plugin that bridges social-media-style hashtag usage with WordPress’s native tag taxonomy. This plugin scans your post content, identifies anything starting with a pound (a.k.a. hashtags sign #), and turns it into a functional part of your site’s tag structure. You no longer have to manually scroll down to the “Tags” meta box every time you want to categorise a quick update. A live front-end demo of this plugin can be found @ <a href="https://lornatimbah.com" rel="nofollow ugc">LornaTimbah.com</a>.
Features:
v.1.0: 
– Automatic hashtag detection in post content 
– Auto-create missing WordPress tags 
– Auto-assign hashtags as tags on save 
– Convert hashtags into clickable links to tag archive pages 
– Simple settings page (enable/disable + mode toggle) 
– Standard Posts support

Tag My Hash

Automatically converts #hashtags in your posts into WordPress tags and clickable links to tag archive pages.

The artifakt Hashtag Plugin vs Tag My Hash