I am using cheap shared no traffic limits web server and I got a link through to slashdot, which was quite an exciting thing to happen. I got 20k pageviews in a day, and 15k unique visitors. The web server worked just fine with no evident lags - or complaints from the hosting company. So it can be cheap, and scalable. Here's the slashdot article: http://developers.slashdot.org/article.pl?sid=09/03/16/192211