Do You Allow Yahoo to Index Your Forum Site? I don't. I block the bot using noindex meta and robots disallow. Yahoo's slurp is too aggressive. One time, Yahoo crashes my server. Yahoo should index sites like Google does. Smooth. Non-aggressive. Suave.
I am considering blocking Yahoo! slurp too. I get so little traffic I hardly think it's worth it. I get more traffic from a forum signature than Yahoo. MSN brings me more traffic.
Of course I let Yahoo index my forums. 95% of my traffic from SE's is from Google but every visit from other SE's helps! So what if you get minimal traffic from Yahoo, that minimal traffic could turn into new participating members on your forum. That's something no forum owner should be passing up, as that's how forums grow. You need to tap into all arena's of traffic. I am on shared hosting with a very active/trafficed forum. I have NEVER had any issue's with Yahoo indexing my site. If your host can't handle it then I think it's time to find a better host.
It's easy to say that, but until you experienced what I did, you will never say this statement again. Yahoo is very aggressive. Its boots can go wild and eat your server resources. Trust me, been there, done that.
Every month my forum gets around 8,000 - 10,000 uniques from yahoo. This makes it my 3rd or 4th highest source of traffic. I would have to be nuts to block yahoo and loose that many visitors every month. If yahoo pulls your server down that much, maybe you need a bigger server? I'am not trying to be rude, but seriously. Is your server running at near maximum right now? On average my server uses around 50% - 75% of its resources. This leaves 25% - 50% free resources at all times. My server averages around 30% free resources. Out of 1.1 gigs of memory, I usually have around 300+ megs free. If the yahoo bot can bring your site down with a normal crawl, what would a surge in traffic do? If your server is right there on the edge, maybe you need to upgrade your hosting package?