Why are some hosts browsable and some are not?

Some do not even show an ip address.

The biggest reasons I can think of are.

1. They have chat disabled.

2. They are behind a firewall.

3. They are not sharing any files.

4. They don't have LimeWire configured properly.

5. They are using a none routeable IP

6. Any combination of the above reasons.

7. There may be other reasons also, but to many to list.

Have a great day.