yahoo.com and hotmail.com were briefly on sc.surbl.org due a blank line getting onto a whitelist. That problem has since been corrected and all the lists are working normally again.
Here's a little more info:
1. A blank line got into the whitelist due to some unexpected input to a script. That case is now handled at both an input script and an output script. It should be impossible again. (UNIX join gets thwarted by blank lines.)
2. yahoo.com and hotmail.com were on the SpamCop spamvertised site data. People really should not be reporting these sites to SpamCop. Frankly the reporting users are being rather careless in doing so since neither hotmail nor yahoo are reportable spam URI destinations. But that's why we have whitelisting, etc. to clean those up.
With the whitelisting broken, they were getting through on sc.surbl.org. They don't appear on other SURBL lists, because the other data sources would never deliberately list them.
It also means those were reported in sufficient quantity to make it onto sc.surbl.org which currently requires 10 reports, but in future will require many more (in a different style of counting).
Jeff C. -- "If it appears in hams, then don't list it."