I think a lot of these sites (like the one without a completed title) that don't deserve to rise in SERPs are not actualy rising, they just aren't being penalised like the ones above it. If your crappy site was 21st and had no backlinks and hence didn't get penalised it will be number 1 after the 20 sites above you get penalised. It doesn't mean you did anything right, it just means you didn't do anything wrong. I really think a lot of these sites will be back in a day or so, it's exactly what happened after the one last week. There's some sort of manual/semi-manual review that's going on and some of them will be back. I also don't think this is the time to make major changes to your site. If Google sees a huge change to your site's structure or backlink methods imediately after this algo change, you could stay there permanently. It could look like you're trying to game the SERPs.