One of the exciting things about the early web was that it was fully bidirectional. Since almost all of the early Internet connections were symmetrical, anyone who could read the web could publish on the web. Web server software was lightweight, and installing it was the only barrier to publishing a site. Every Internet-connected computer was a "host", not a "client" or a "server".
This changed with the introduction of asymmetrical broadband connections and client-oriented systems (read: Windows 95 and successors). Vendors made the assumption that we wanted to consume content, not create and manage it.
Now, finally, the tide is turning. Although most residential and small-business broadband connections are still asymmetrical, the upstream bandwidth is sufficient for medium-duty serving. Here in Toronto, a 3-8 Mbps download/800 kbps upload speed is very common and priced between $40-60. The 800 kbps upstream speed is half of a T1, which used to be the standard business-class data connection, and is sufficient for serving a low- to medium-volume web site. Although some ISPs such as Rogers and Bell still haven't grasped the concept (and may never), other ISPs such as TekSavvy are run and staffed by smart people that understand the demand for unencumbered, fast pipes. Most non-Windows operating systems do not distinguish between client and server roles and are happy to be both.
We're seeing the bidirectionial internet appear in other places too: browser extensions that provide services traditionally supplied by "servers", personal domain names, and SMTP and DNS servers running in homes.
The return of the bidirectional internet: is an exciting and empowering change that's well overdue.
But what stops me from serving web content from my computer isn't bandwidth asymmetry but protocol asymmetry. My ISP assigns my computer a private IP, basically unreachable from the outside world. As I understand it, if I wanted to install MediaWiki and go to town, I'd have to pay for more expensive internet service-- with a static IP and the ability to open ports in the firewall.
ISPs use the comsumer/producer distinction to segment the market. They've obeserved that producers have deeper pockets. Would-be producers that aren't rich have to find some other way to participate.
Jason: You get a NAT'ed IP address from your ISP? I'd imagine that is fairly uncommon.
Chris: Funny you should mention Teksavvy. I just this week discovered them and switched from Rogers cable. The switching points for me were a) no traffic limits, b) nothing banning servers in the TOS, and c) real tech support who actually answer tough questions and don't just read from a script.
Things like traffic shaping didn't affect me (yet), but the point you make was a part of my decision: the Internet is viewed by companies like Rogers and Bell as a medium for consumption, and as far as they're concerned, if you want to be a producer, you shouldn't be using a residential internet service.
Jesse: Yep. Happens to my sister, too, on a totally different ISP-- so it can't be that uncommon.
Even if I got a real IP, it'd be dynamically assigned, which I guess means figuring out dynamic DNS or something. I've never had to figure that out; I'm guessing it probably wouldn't be hard... but at the same time, probably tedious enough to stymie your average non-geek.