[kysol]

It really depends on the ISP. A static IP generally has to be requested, and at a cost. Additionally, some ISP's like to be restrictive blocking inbound low ports such as 25, 80, 443 - so hosting a web server off your home connection might be a problem depending on the ISP.

[sliverstorm]

It's specifically against residential Comcast ToS, for example, to host a publicly-accessible website.