yahoo not working on pidgin this days, how to fix it: (see the thread)
 

yesterday yahoo wont work for me till now then I have searched the net for this issue until I have found this solution:
add this line (66.163.181.170 scs.msg.yahoo.com) to your /etc/hosts
this will make your yahoo work for you again ;)

source:
http://stuff.techwhack.com/6804-yahoo-messenger-pidgin

Pidgin 2.5.7 "fixes" the above issue.

yeah but till now ubuntu havnt updated her repos to the last pidgin 2.5.7
and then ppa pidgin in launch-pad too they are still using 2.5.6 :(

i was having same problem for last one week. got fixed with this. thanks bro.

now you can add the pidgin developers ppa from here and update to the last pidgin 2.5.7, in this release they fixed the yahoo issue

Its nothing but changes in messenger server with yahoo.
which is affecting third party messengers than yahoo.
for that pidgin has release there newer version of messenger
and existing pidgin user has to make some changes in there
messenger server setting.need to replace existing messenger
server i.e (pager server) from scs.msg.yahoo.com to cn.scs.msg.yahoo.com this will resolve the issue.

Cheers
Sandy.

So is my hosts file supposed to look like this?
In the meantime, I tried Getsandy's solution; it worked. I'm seeing messages elsewhere to the effect that the latest pidgin does not solve the problem.

You shouldn't need to edit hosts at all. I guess this was some early workaround.

2.5.7 certainly fixed the issue for me. i note that there is now a 2.5.8 out. This seems to have fixed an msn issue, but I'm not sure how related the issues were.