General chatter recently suggested that Google was updating - as of yesterday a significant algo change hit the SERPs. A lot of SEO's and seo-savvy webmasters are reporting significant loss of rankings and traffic for their own and client sites, and typically there are complaints about irrelevant rankings.
There's widespread speculation as to what is behind the changes - main theories at present are:
- Data loss at Google causes an incomplete index - suggestions of Googlebot panic spidering to rebuild it
- Semantic processing of links that mean established and varied links are weighted more, giving more power to internal links and less weight to link development work
- New filter for site-wide links
- Increased weighting of authorities to reduce presence of less established sites even further, to limit spam
- Google is evil, blah blah blah