OK, so I made a new site on a new domain about 3 weeks ago now. After getting the domain indexed in about 5 days, I did very minimal link building over the next week. I then started commenting on top commentator blogs, getting me sitewide links on about 10 blogs (in a few days). My long tail traffic was growing. Then, a few days ago, every single bit of my rankings/long tail keywords bringing traffic disappeared, and I haven't received any traffic for about 4 days now. My site is still fully indexed in Google however. Is my site banned or sandboxed?
It is sandboxed. If it was banned you would not be able to find it at all in google. Your site is 3 weeks old, that just confirms that its in the sandbox. Keep building links, it might take you a few weeks or a few months to get out. Depending on the strength of your backlinks.
It's quite frustrating to see your website suddenly nowhere in Google. But it doesn't mean it is penalized or banned in Google. Here are the few steps to know whether your website is banned or penalized in Google or not? Is your website indexed in Google, use the site: command (site:domain.com) Is your website still ranked for domain name or other unique branded keywords. Is your website ranking for 4-5 unique keywords present on page Title tag of the website.
your site is jus sandboxed...if it were banned, you wouldn't see a single listing on google of your site. This doesnt mean on other people sites like Digg etc...If you are seeing a single link to your actual page, then its listed. You just need to give it time to settle into the engine and work its way threw the ranking systems.