You can set the no. of minimum files a person must share by going to Tools>Options>Advanced>Preferencing (But the slider doesn't work!)

Just b/c you can't browse somebody's files doesn't mean they aren't sharing. There's many reasons & some unknowns why people can't be browsed. Generally having Chat enabled helps to browse or direct connect with somebody. You'll notice that generally in the monitor window only those that have the chat enabled are the ones you can successfully browse. For more about chat enabling & dc see: http://www.gnutellaforums.com/showth...threadid=30911