I am so sorry , but you may need to update your site often and don't link to sites for free as this may damage your reputation and don't submit your site to web directories as this may hurt your pr badly if these directories are being banned by Google for suspicious linking.
Why dont you ask Matt cutts? evidently you have in the past as your yahoo links show him as the first few links pointing to your site from his blog... laterz malcolm
Maybe cos he realized that Matt is busy this week and won't be able to answer quickly. Anyways, if you didn't make any or some major changes, then everything should be back normal. Which tool are you using? Maybe there is some problem with the tool.