We have all dealt with WordPress search in the past. It might work fine when you are getting started. But you are going to need additional tools and scripts to offer the best search experience on your established website. Have you ever wanted to allow your visitors to search through comments on your site? These 3 comment search plugins have you covered:
Relevanssi: a better search solution for WordPress. Replaces the default search with partial-match search and sorts results by relevance. You can search comments, tags, categories and custom fields.
Search Everything: improves WordPress’ search functionality and lets your visitors search every page, tag, comment, draft, or attachment. It offers search highlighting too.
WP Search for Comments: as the name suggests, this plugin lets you search through comments on your website. It offers AJAX pagination and can be added automatically. The plugin also offers search highlighting.
There are other ways to enhance the default search system in WordPress. If you just want to allow your visitors to search within your comments, the above plugins have you covered.