Add your site to guard.
Check connectivity of all link in your site(ref of other webpages, CDN and even inner links) regularly.
As time pass by, site you referenced maybe out of date,
CDN you used maybe down due to tech issues(or by GWF ..)
Usually these things will give your user a 404 or even break your page style.
All these things are NOT user friendly.
With link doctor, it will check your site regularly and tell you whether links in your site is OK.
Note: This is only the very first version, and for demo use only.