The speeds provided on this site are those that the data provider has indicated as the likely speed of an Internet connection to these premises. This speed (more correctly called 'bandwidth') is a measure of how quickly data can be sent down that line. For example a speed of 60Mbps means that twice as much data can be transferred in the same amount of time as a speed of 30Mbps. Having said that, the speed of your connection is only the maximum speed that you can access Internet with and may not mean that you can access the Internet with that speed all the time. This is because there are a number of other factors that come into play, including any congestion on the local network and any on the ISP's network, and the effect of those factors can change throughout the day.
For some technologies we note that the speed is variable because the actual speed of connection is affected by the distance the signal needs to travel and any interference in the signal quality. The range of speeds then indicates the range that is possible given those variable factors. For the other technologies we note that the speed is fixed, which means that it is not affected by the quality of the connection. In those cases the range of speeds indicates the range of speeds that you can choose to purchase.
This is the speed at which data comes into your premises and that's important for everything from browsing web pages to downloading software updates. It is especially important for video and other applications where a lot of data needs to be transferred quickly. Different content providers make different recommendations regarding minimum speeds:
One way of comparing download speeds is to see how long it takes to download a file. A DVD is roughly 4.7GB and over a 2Mbps connection that would take around 6 hours to download while over a 100Mbps connection it would take around 8 minutes (assuming you don't get slowed down by congestion).
The Internet is not all about consuming content and if you want to produce and share content then upload speed is important. For example you may wish to upload a video to a video-sharing site, or you may run a game server at home. For ADSL/VDSL upload speed is often slower than download speed on the same connection because the copper connection only has a finite speed and Chorus assign more of that to the download speed than the upload speed. For other technologies it is possible to get equal download and upload speed if you wish.
Video chat is a good example of where you need to send data as quickly as you receive it and so upload speed is important. For example, the Skype figures for download speed given above are also their recommendations for upload speed.
Having the fastest Internet connection may not help if the datacap is too low. Even a 2Mbps connection can download over 20GB in a day and a 30Mbps connection over 300GB.
Latency is how long it takes each individual packet to traverse the network and that becomes important for when computers need to react quickly to something happening on the connection. For example, gamers aim for a low latency because they need to react quickly in the game, or if you have a high latency connection then there will be a noticeable delay after you click on a web page before it loads.
The latency you experience on a connection is determined largely by how far the packets need to travel and the limit imposed by the speed of light on how quickly they can do that. Satellite connections will always have high latency because the satellites are 36,000km away. Because the rest of the world is so far away from NZ the latency to international sites is higher than experienced in other countries and it doesn't matter how fast the connection is, that can't be overcome.