Currently the search only seems to include the body of the topic rather than also the title, which can result in threads not being found when the text you're searching for isn't repeated in the topic's body.
Why would it be useful?
Searching the title is especially important with tag alias/implication requests and BURs since the text is often not repeated in the body of the forum since usually a short reason is provided and the request itself is now dcode like [ta:####]. This can result in duplicate requests like topic #32142 when existing requests can't be found through the forum search. It's also just annoying when you can't find a specific thread you were looking for when you know what the title was.
What part(s) of the site page(s) are affected?
https://e621.net/forum_posts?search