Yahoo's WHOIS records borked?

I don't quite get it - is this some weird hack people do to get their domains in to whois listings for other companies?

Is this just whois spam, or is there something more going on?

no, it's not. That's a digest response. You need to redo the lookup as =yahoo.com to get their record:

#whois =yahoo.com

(scroll to bottom for yahoo.com listing)

Whois Server Version 2.0

Domain names in the .com and .net domains can now be registered with many different competing registrars. Go to http://www.internic.net for detailed information.

   Server Name: YAHOO.COM.ZZZZZZZ.GET.ONE.MILLION.DOLLARS.AT.WWW.UNIMUNDI.COM
   IP Address: 209.126.190.70
   Registrar: DIRECTI INTERNET SOLUTIONS PVT. LTD. D/B/A PUBLICDOMAINREGISTRY.COM
   Whois Server: whois.PublicDomainRegistry.com
   Referral URL: http://www.PublicDomainRegistry.com

   Server Name: YAHOO.COM.ZZZZZZ.MORE.INFO.AT.WWW.BEYONDWHOIS.COM
   IP Address: 203.36.226.2
   Registrar: TUCOWS.COM CO.
   Whois Server: whois.tucows.com
   Referral URL: http://domainhelp.opensrs.net

   Server Name: YAHOO.COM.ZZZZZ.GET.LAID.AT.WWW.SWINGINGCOMMUNITY.COM
   IP Address: 69.41.185.196
   Registrar: TUCOWS.COM CO.
   Whois Server: whois.tucows.com
   Referral URL: http://domainhelp.opensrs.net

   Server Name: YAHOO.COM.ZOMBIED.AND.HACKED.BY.WWW.WEB-HACK.COM
   IP Address: 217.107.217.167
   Registrar: DOMAINCONTEXT, INC.
   Whois Server: whois.domaincontext.com
   Referral URL: http://www.domaincontext.com

   Server Name: YAHOO.COM.VN
   Registrar: MELBOURNE IT, LTD. D/B/A INTERNET NAMES WORLDWIDE
   Whois Server: whois.melbourneit.com
   Referral URL: http://www.melbourneit.com

   Server Name: YAHOO.COM.VIRGINCHASSIS.COM
   IP Address: 66.218.71.205
   Registrar: DOTSTER, INC.
   Whois Server: whois.dotster.com
   Referral URL: http://www.dotster.com

   Server Name: YAHOO.COM.TWIXTEARS.COM
   IP Address: 66.218.71.205
   Registrar: DOTSTER, INC.
   Whois Server: whois.dotster.com
   Referral URL: http://www.dotster.com

   Server Name: YAHOO.COM.TW
   Registrar: GODADDY.COM, INC.
   Whois Server: whois.godaddy.com
   Referral URL: http://registrar.godaddy.com

   Server Name: YAHOO.COM.SINGERPAT.COM
   IP Address: 98.136.43.32
   IP Address: 66.196.84.168
   Registrar: GODADDY.COM, INC.
   Whois Server: whois.godaddy.com
   Referral URL: http://registrar.godaddy.com

   Server Name: YAHOO.COM.SG
   Registrar: DOTSTER, INC.
   Whois Server: whois.dotster.com
   Referral URL: http://www.dotster.com

   Server Name: YAHOO.COM.MX
   Registrar: DIRECTI INTERNET SOLUTIONS PVT. LTD. D/B/A PUBLICDOMAINREGISTRY.COM
   Whois Server: whois.PublicDomainRegistry.com
   Referral URL: http://www.PublicDomainRegistry.com

   Server Name: YAHOO.COM.MORE.INFO.AT.WWW.BEYONDWHOIS.COM
   IP Address: 203.36.226.2
   Registrar: TUCOWS.COM CO.
   Whois Server: whois.tucows.com
   Referral URL: http://domainhelp.opensrs.net

   Server Name: YAHOO.COM.JTNELECTRIC.COM
   IP Address: 66.218.71.205
   IP Address: 216.109.116.20
   Registrar: GODADDY.COM, INC.
   Whois Server: whois.godaddy.com
   Referral URL: http://registrar.godaddy.com

   Server Name: YAHOO.COM.IS.N0T.AS.1337.AS.SEARCH.GULLI.COM
   IP Address: 80.190.192.24
   Registrar: EPAG DOMAINSERVICES GMBH
   Whois Server: whois.enterprice.net
   Referral URL: http://www.enterprice.net

   Server Name: YAHOO.COM.HK
   Registrar: ENOM, INC.
   Whois Server: whois.enom.com
   Referral URL: http://www.enom.com

   Server Name: YAHOO.COM.ELPOV.COM
   IP Address: 66.21.71.205
   Registrar: FASTDOMAIN, INC.
   Whois Server: whois.fastdomain.com
   Referral URL: http://www.fastdomain.com

   Server Name: YAHOO.COM.EATINGFORJOY.NET
   IP Address: 66.218.71.205
   Registrar: MYDOMAIN, INC.
   Whois Server: whois.dotster.com
   Referral URL: http://www.dotster.com

   Server Name: YAHOO.COM.DUVALMANIA.COM
   IP Address: 98.136.43.32
   Registrar: GODADDY.COM, INC.
   Whois Server: whois.godaddy.com
   Referral URL: http://registrar.godaddy.com

   Server Name: YAHOO.COM.DALLARIVA.COM
   IP Address: 66.218.71.205
   Registrar: DOTSTER, INC.
   Whois Server: whois.dotster.com
   Referral URL: http://www.dotster.com

   Server Name: YAHOO.COM.CN
   Registrar: BEIJING INNOVATIVE LINKAGE TECHNOLOGY LTD. DBA DNS.COM.CN
   Whois Server: whois.dns.com.cn
   Referral URL: http://www.dns.com.cn

   Server Name: YAHOO.COM.CHRISIMAMURAPHOTOWORKS.COM
   IP Address: 66.218.71.205
   Registrar: TUCOWS.COM CO.
   Whois Server: whois.tucows.com
   Referral URL: http://domainhelp.opensrs.net

   Server Name: YAHOO.COM.BR
   Registrar: ENOM, INC.
   Whois Server: whois.enom.com
   Referral URL: http://www.enom.com

   Server Name: YAHOO.COM.BGPETERSON.COM
   IP Address: 66.218.71.205
   Registrar: DOTSTER, INC.
   Whois Server: whois.dotster.com
   Referral URL: http://www.dotster.com

   Server Name: YAHOO.COM.AU
   Registrar: WILD WEST DOMAINS, INC.
   Whois Server: whois.wildwestdomains.com
   Referral URL: http://www.wildwestdomains.com

   Server Name: YAHOO.COM.ACCUTAXSERVICES.COM
   IP Address: 98.136.43.32
   IP Address: 66.196.84.168
   Registrar: WILD WEST DOMAINS, INC.
   Whois Server: whois.wildwestdomains.com
   Referral URL: http://www.wildwestdomains.com

   Domain Name: YAHOO.COM
   Registrar: MARKMONITOR INC.
   Whois Server: whois.markmonitor.com
   Referral URL: http://www.markmonitor.com
   Name Server: NS1.YAHOO.COM
   Name Server: NS2.YAHOO.COM
   Name Server: NS3.YAHOO.COM
   Name Server: NS4.YAHOO.COM
   Name Server: NS5.YAHOO.COM
   Status: clientDeleteProhibited
   Status: clientTransferProhibited
   Status: clientUpdateProhibited
   Status: serverDeleteProhibited
   Status: serverTransferProhibited
   Status: serverUpdateProhibited
   Updated Date: 30-nov-2011
   Creation Date: 18-jan-1995
   Expiration Date: 19-jan-2012