All this means is that the company providing the bandwidth is not calculating how many bytes are being transferred back and forth but there are still limits to what you can transfer. For instance if you are connected through a 10 megabits per second port (10mb) then the theoretical limit is that many bytes per second and once the ceiling is reached no more bytes can travel through that connection, they get dropped. Even if the company has a burst setup then there will be an upper limit to that. Perhaps they are on a 100mb feed, so the limit there would be 100 mb. By the way, a 10 mb feed does not actually provide 10 mb as there is overhead that reduces the actual throughput. Typically a 10 mb feed would provide closer to 7mb of actual usuable throughput.
24 X 7 Support:
This can mean almost anything. Larger companies will actually have staff on hand in the wee hours but you can be sure that in most cases these are not level 3 technicians and any serious issue will have to wait for daytime staff. Smaller hosts will range from emergency numbers that page someone through to the simple fact that you can send an email and the email will be received by the mail server but will anyone actually look at it.
Dedicated Servers with 3000GB of Transfer
This one really gets me. Dedicated servers with that much transfer but when you start to read the details, they talk about options like upgrading to a 10 Mb port or even upgrading to a 100 Mb port and these options never seem to be very cheap. So the trap here is if your port is less than 10 Mb then you cannot physically get those 3000 GB of transfer. I was looking at one of my competitors offerings and they include with every server an unmetered connection. They go on to explain it is a 1.5 Mb connection. This is a reasonable offer and one that makes sense. Our sponsor, Chinook Webs also offers these types of unmetered connections, they are an excellent value.