SEO Issues?

Which search engine have you had problems optimizing to work with your website?

I have had problems with Bing, since its Webmaster Tools weren't really stable when it was released, there were a couple of crawling issues which I had encountered but now Bing is working for me since my SEO plugin updated towards being Bing friendly.

I've been having problems with Yahoo search engine.
My website ranks great on yahoo.ca for "money forum", but when you search on yahoo.com, you can't find my website anywhere.
I'm starting to rank good on Google and MSN but Yahoo is just giving me troubles and I can't find why.

My site seems to work well with google, I think I have got it well optimized.

Mine are working well with Google and Yahoo. MSN is the one I faced a bit of trouble with. Bing is new and will take some time to settle down.

Yeah Bing has trouble with lots of people at the moment I think.