In other day, your pidgin program don't show buddy in byddy list, what happen ? I recent meet this problem today, after search google to find the way to solve. But nothing was found except this link, from launchpad bug report center . But still have nothing. Another way ?
I try to reinstall pidgin, it start and run nomally . I guess this problem occured with me because my account setting. I compare the new setting with my old setting and discover some thing different . I try to change my old setting then, when i change my account server address, this problem was solved .
Change the server name by go to Accounts.Manager Accounts, choose your account, click on Modify. In tab Advance, change Pager server to scsa.msg.yahoo.com and Bingo! this problem was solved.
Have fun !