We've just installed this in a clean 7.3 on prem install, only issues we had were related to some relative paths for css files (looking at web root for the lib folder not CustomPages/yammer), but easily fixed, however it doesn't seem to have the expected functionality.
The Yammer Tab from MyCRM works fine, can post, and loads up the history
The Tab from a Company allows you to post but is empty each time you load it, ie it doesn't load up any history, so you can't see any conversations tagged to that company (not much use)
There are no other tabs, eg despite having the following ticked in Admin;
Yam from Company context?
Yam from Person context?
Yam from Opportunity context?
Yam from Case context?
Yam from Communication context?
Yam from Lead context?
There is no Yammer tab against Person, Oppo, Case, Comm or Lead - is there something significant we're missing, I can't even see the relevant .asp pages for other entitites, unless all contained in yammer.asp or yammer_company_wall.asp?