say that you are a egotestical maniac bent on ruling the gnutella world and you think your program is the best so you make a plan to somehow have your client connect to itself mostly without alerting others
how do you do this?
lets say you call your program "bare" because you download naked ladies all the time, it's the best program available!
your plan is amazingly clever, you use the new pong caching! what is that?
every time you connect to another gnutella client it will return about 10 IP addresses of other clients out there so you can build a cache of others to connect to
say that your ego is so big you just couldnt resist and decided to only return IP addrs of "bare" clients only!
this would create a little private network of bare clients and you rule the world!!
anyone who connects to you will then use your list to connect to other clients, which are all bare, and then those bare clients will send more addrs of bare and you rule the world!
wait! someone might find out, so you simply write a little random thing that picks a few non bare IP addrs just to save face, but then your ego decides to leave that out

since you are having fun and rule the world anyway, you make your client start sucking up all the open incoming connections on any non-bare client by constantly connecting to any non-bare client you find, connect, send some pongs all over the network and disconnect, and I mean really hit them over and over without delay
don't do this to your own clients, you need to keep a list of known addrs for bare clients so you don't bother them
and just for fun, if they are mostly connected to your private little bare network, don't hit their incoming ports because you can use them to suck more people into the bare network
now you have a core circle of bare only clients surounded by those crappy competing clients and you can make them look real bad by sending them less results and delaying packets to them
you can get even more fancy and wait till they send out a search, then drop the connection! This should make the bare client look good and make it more popular ($$$$)

real life true story, this is happening now and is why greed doesn't belong on gnutella
its time to start blocking those clients that behave like this
it would be easy to id those clients and if you get too many connections of that type, ban it for 30 minutes