Yesterday I noticed a warning in my Google Webmaster Tools. It told me that one of the posts on my blog had a slow load time - a post which happened to be by far the most commented on. So, to rectify this, I lowered the maximum number of comments per page to 50 and resubmitted my sitemap. (This means that newer comments appear on a separate 'comments page'.)
Now I've noticed that my site has slipped to #2 for my top search term, for which it had ranked #1 for since October '13. So this got me thinking: has my decision to move the newest comments to another page affected it badly? Reduced its freshness, maybe? Or could the negative effect have come from the resubmitting of the sitemap?
Edit: Also, just checked. CTR was increasing, as were number of social media shares.