areacodes.org is a placeholder web site. There are many sites out there that provide area code lookup, but they keep changing, going away, requiring logins, etc.
We got sick of chasing these sites around, so we set up areacodes.org. We provide a link or a form to a good area code lookup site. If it goes away, someone (you) emails us to let us know the site isn't working, and we find another site that does.
For you, it means you just need to come to areacodes.org when you want to find an area code.