Google has just released a handy tool to the webmaster portal that shows you all of your 404 errors with a link of pages that link to them.
As Matt Cutts explains, it’s an easy way to get some links to your site. There are probably sites out there that meant to link to you, but messed up a character, or put an extra letter on the end or something, resulting in a 404 error (and no link juice). By noticing that error and contacting the linking site, that link will become beneficial.
You could also just create a 301 redirect from the broken URL to whatever page they intended to link to. The advantage to this is that you wouldn’t have to wait (and hope) for the other site to fix their link. The downside is that it could become cumbersome to manage if you have a lot of them.
In any case, there is a lot of usefulness to be found with this tool. I’ve been digging through my sites and finding some jems, so give it a shot!
