How long does it takes for you achieve 5K visitors to your single blog? I guess professional bloggers may have answers? I personally run various blogs and sites, seeing it took almost 1 year to reach 1K hits from Google in daily basis
Its totally depends on your keywords, your seo work and your content. If you have good and informative content with the lates updates and you do a lots of quality seo work with social networking then it would be easy. But 5k needs really a much more time to achieved.
This totally depends upon Google. Google holds ~80% share for tech-blogs (sends almost 80% visitors from search). So try to be good in Google's view. To do try to get good quality back-links and post unique, quality content.
5,000 unique visitors a day is a great achievement. You will need to have loads of content, consistently build links to all pages of your website to rank each one well, submit your website to thinks like Stumbleupon and other social sites to increase traffic and loads more. It takes a lot of time and hard work to get high visit counts. Maybe try working out a viral campaign that suits your niche? This usually works well with Facebook/Myspace/Twitter.