First of all, what is Google Webmasters Console?

Google Webmasters Console is Google's interface and communication channel between webmasters and Google. They found that while than passively indexing websites using web spiders was effective, sometimes webmasters simply didn't know something on their website was lacking (e.g. dead links, excessive load times, etc.). So this is their way to actively let webmasters who opt in to communicate know.

So what is Google Webmasters Console?