On friday mybloglog shows total number of traffic 580 but google analytics shows 690 unique traffic. Which provide 100% accurate results....
Are you referring to number of page views or number of visitors? Are you comparing the same thing? Are both tracking systems installed in the same location on your site? Just a few things you should consider.
I guess, u put widget of recent visitors on your blog.. if yes, then that data was inaccurate bz some people didn't join ur community on bloglog so might be some visits willnt count as some visitors hadnt join your community. Another reason might be data collection method of each and every web analytics tool is different. you can take example of stat counter and google analytics. but as per accuracy concern i would like to suggest for deploying trust on google analytics for accuracy of visitor details.