The colors are there just to make the availability status easier to read. As you probably know, for most things, you have red as a "this is bad" color , yellow/orange as "this is poor" and green as "everything is ok". With downloads it's just the same:
When you download a green file, there are 2 or more open slots, so when you start downloading from that user, there will still be an open slot for others to get another file from the same user.
Yellow/orange means there's only 1 more open slot. you will get the file, but you'll also use the only slot that is left open, and stuck up others who try to download from that user.
Red means there are no open slots, and you can't get the file unless you queue.
when you see "1 + 1 available", the first 1 (green one) means there's 1 user with an open slot, and the other 1 (red) means there's 1 user with no open slots. (Click the
- in front of the filename, and you'll see
)
