One of the biggest things I noticed was missing from Ghost 0.3 was the ability to search for posts. My pageview count was always very high prior to moving to Ghost, primarily due to the fact that visitors would search the archives for posts with a similar theme.
Luckily, I stumbled across Temacotta's Tapirus in my travels across the Interwebs.
Tapirus is a jQuery-powered plugin that allows for searching static pages (like the content pages on a Ghost blog). The plugin is powered by Tapir.
To get started, you'll need to head over to Tapir's website and provide some basic information - your blog's RSS URL to be exact. Tapir will then provide you with a public key and an private API hash. Following the simple instructions on Temacotta's site, it's not a stretch to say Tapirus could be added to your Ghost blog in 5 minutes or less. The biggest delay is letting Tapir run down your RSS feed and index your content so that the plug-in is actually useful.
I've added it to my blog here and you can test it out using the search box above. There's only one caveat I've found. If you've moved your blog from Wordpress to Ghost (as I did) and your RSS URL has changed, Tapir will only index your Ghost URL (www.example.com/rss). Anything captured under the old Wordpress RSS URL (www.example.com/feed) will not be captured as that URL isn't valid any longer. Because posts published prior to the conversation to Ghost won't be included in the Ghost RSS feed, they won't display in search results.
Despite this one glaring setback that, for some, might be a dealbreaker, I find Tapirus invaluable to retain visitors and keep my bounce rate low. It's important that my site's visitors link up with my previous posts. Otherwise, what's the point of writing quality content?
UPDATE: I no longer use Tapir due to the way it's permanently broken. Check out my latest post on ghostHunter to super-charge your Ghost blog search.