DaddyTimesTwo is exactly right, the only issue is the latency involved with sending the signal up and back down through the satellite.
Some things just won’t work very well, if at all. Multi-player games that require real-time interaction won’t work. Virtual Private Networking (IPsec VPN) probably won’t work (and MS networking inside it definitely won’t). Two-way video conferencing and Internet telephony won’t work.
On the bright side, if cable modems and DSL aren’t an option, it is about the only cost effective broadband solution.
Surfing the web on dial-up is like: click, wait, quarter of a page, wait, half the page, wait, three-quarters of the page, wait, the page.
Surfing on DSL/cable modem is like: click, wait, the page.
Surfing on satellite is like: click, wait, wait, the page.
Streaming video works just fine, btw.
Also, it has some other benefits. Satellites, by their nature, broadcast. Every piece of data that is sent to your computer is also sent to every other dish tuned to that satellite transponder. It is up to your “satellite modem” to figure out what data should be forwarded to your computer. Because of this, satellite providers can offer things that regular ISPs can’t (or don’t).
For example, when I was using satellite internet, the system allowed you to “subscribe” to certain websites (like USA Today, and other media sites). The satellite service would broadcast the entire (current) content of the site overnight, and if you were subscribed, all that data would be stored in a cache on your local harddrive. In the morning, when you went to look at that site, all the data was on your local drive, and there was no delay at all in displaying it. Pretty cool, actually.
Bottom line: If you have no other options, want broadband, and are willing to pay their fee (which is comparable to DSL, IIRC), and don’t require realtime interactive applications, go for it!