Another quick comment about so-called 'leechers'...

People who are making themselves available to be Ultrapeers, and thereby benefiting the entire Gnutella Community, should not... ideally... Should NOT be sharing.

Perhaps there are some Ultrapeers who have such bandwidth capacity that it is possible for them to do a modest amount of sharing, but this is not the norm.
Many users who are acting as Ultrapeers do not in fact have the capacity to do the 'job' properly... When they are sharing as well as acting as an Ultrapeer, the Ultrapeer functions 'suffer'.

Many Ultrapeers know this, which will explain why you can so often see that an Ultrapeer is either sharing zero content or very, very little.

The entire question regarding so-called 'leeches' is not a simple one to resolve... But, the worst possible solution(s), such as 'punishing' people who are not sharing by either attempting to 'block' them or perhaps hiding their shared folders, are simply stupid.

I hope everyone will THINK before branding anyone a 'leech'.