On the surface, crawling syndication feeds looks like an attractive ideafor web spider operators (although I am not convinced that the metadatathey get is on the whole any better than the metadata on web pages).But as things are today, it is a terrible idea and is highly likely toprovoke bad reactions if attempted.

The big problem is that right now, if you turned a web spider loose onsyndication feeds it would pull far too many of them. This is becausepeople (and websites) have lots

Recently, I have wound up wondering if using or not using tcpdump 's -p switch made any difference on modern hardware and modern switchednetworks (partly because not using it causes your kernel to generate amessage every time you start and stop tcpdump , and I can live withoutthat). The somewhat unfortunate answer is that yes, it still makes adifference.

First, promiscuous mode is still at least partly a low level hardwarething in your network card, not just a software switch inside thenetworking stack.