You said you talked to a client? Were you selling a link to him based on your PR? If you sell links, someone may have reported you to Google and then Google has taken actions. Sounds the most probably reason for me in that case... Rainer
i guess that client was matt cutts. Read my reply 5 times to understand why ur Pr went from Pr 4 to Pr 0 in no time.
hey guys, I have real all your comments related to Google PR. As per my knowledge, Google has updated this PR algorithm. If your site are getting backlinks from link sells site then your site's PR might be down 2 to 3. As Google might be considered it as directories or sites which are selling links don't provide the appropriate result to the user's query. And, Google does not do or count anything which are not able to provide best result to users. I certainly say that your backlinks are coming from sell links directories or sites and your PR down. But, I think that by decreasing PR, your traffic won't be affected. Then, don't be frustrated by getting PR down and Keep smiling.