Why are some sites unavailable?
Our intention is to provide a helpful service, and in no way be malicious to any site. However, some sites get a lot more traffic because of us, and we end up taking down their sites. To help these sites from being over burden with a take down, we disable the site for a bit. This is the case with most sites, but some, like LinkedIn, just have us black-listed. We are working to fix this, though.