There was a silly bug in the indexing code, it only picked up URLs from links, but not images. I've [heard some rumors](http://chat.stackexchange.com/transcript/message/35974192#35974192) about Regex parsing HTML...

Anyway, after the HTTPS rewrite, the posts received a new timestamp and were picked up by the incremental indexing process: http://askubuntu.com/search?q=url%3Ahttps%3A%2F%2Fhostmar.co