why i cannot access my website with its ipaddress. but only with sitename. Is this common?

Not knowing the server on which you are running, but in IIS, there is the host-header mapping function.

This allows multiple websites to run from the same IP address, but requires that the domain name of the web site is supplied as the "Host" http request header. The server queries this header and serves the content from the appropriate site.

Any request coming in via the IP address will not have "waycoolblog.com" as the host header. If your server is hosting more than one web site, chances are that yours is not the 'default', so the server won't serve your site.

Maybe the server your site is on is using hostname-based VirtualHosting?