Well, they'll try. The relay plays a similar role to a search engine, though without the ranking. Why do different search engines have different content? As ot

Well, they'll try. The relay plays a similar role to a search engine, though without the ranking. Why do different search engines have different content? As others have said, spam and illegal content are the most likely reasons. We might also compare to email delivery; maybe ideally every message would be delivered, but in the real world, they aren't, and open relays are a hazard.