My site had about 70 backlinks and PR4. Since yesterday, my PR has gone to 0 (full white bar) and today, when I entered "link:www.(-mysitehere-).com", it returned zero results. I know it hasn't been banned or anything because the site is still quite impressive on the SERPs, plus I haven't had any risky link exchanges or optimising done...not now, not ever. Has anyone noticed anything similar? Is ithis possibly an update of backlinks or PR?