We implemented search on our help site (http://help.simpletax.ca) using the excellent lunr.js (http://lunrjs.com) + this Jekyll plug-in (https://github.com/slashdotdash/jekyll-lunr-js-search). The search index is updated when you build your Jekyll site, so it's a piece of cake to maintain and gives you full text search. I don't know how well it would scale, but if you are in the hundreds of posts, you should be ok.