Also, what is the 8mg thing? I see it on all the sites for internet here. And download limits? What constitutes a download (is it pictures or iTunes or something)?
8mg?
Could it be 8 meg, referring to a speed of 8Mbps? Either that or 8GB, indicating a monthly download limit of 8 gigabytes.
The download caps are the
total amount of data which is sent to you during the month. It will include web browsing, e-mail & attachments, files received over FTP -- Basically everything which comes down the DSL connection to your computer.
How does that work? I know Virgin have their own cable connections but other than them I didn't think anyone else had the physical infrastructure to provide broadband with out using BT's wires.
Other than the cable companies, they don't. Every DSL connection goes over BT lines, which is now handled by the fairly new BT OpenReach division (with the exception of the Hull area, with its independent phone company).
From the technical point of view there's no reason why DSL cannot be provided on a line which doesn't have POTS (Plain Old Telephone Service) on it as well. This is sometimes referred to as "raw DSL" or "naked DSL." It would be down to whether BT OpenReach will provide the line at a cost acceptable to the ISP (and you) when BT isn't receiving any other POTS income from it.
If you will be served from a central office which has no local loop unbundling, your DSL connection will be provided by BT Wholesale back to wherever your ISP has a presence anyway. You can check for LLU options by exchange here:
http://www.samknows.com/broadband/search.php