I hear Yahoo! and other major websites were hit with a DDoS attack over the weekend, resulting in several outages across their web services. It's been 48 hours now since I was last able to access web mail from Yahoo!. Being a premium member, that means I can't get my business mail through POP3/SMTP either. But thank God for alternative [free] mail services - I pity anyone that depended solely on Yahoo! for their mail needs.
Unfortunately, an event like this is all it takes to pull the plug on my accounts there. I know their IT team is frivolously working to resolve the problem, but 2 days is too long for some of us to handle. Worst still, there's no public statement about the problem, sometimes causing users to question their connections or wonder if they are being blocked somewhere. Luckily, IM still works.