Google’s made some very big changes in the past couple of weeks, and it’s affecting more sites than previously expected. In what way? Depending on how SEO has been done, some sites are dropping a few positions, some are dropping by multiple pages.
Google made their main site (Google.com) more secure a few months back by adding SSL security to all searches inside of personal accounts. Well now they’re stepping it up a level further and adding SSL search to all of their other sites.
If it’s a priority enough for Google, we may see this start happening across many more sites before too long.