Alibaba is a pretty bad example to use, because Yahoo made $9.4 billion because they DID invest in Alibaba early on.
Jerry Yang made the investment in Alibaba circa 2005. If you told him Yahoo! will be investing in Snapchat he would probably laugh at you.
Now in 2014, Yahoo! is buying a blogging platform and investing in picture messaging with a timer.
The driving force overseas is money, money, money. Not impressions or # of useless users.
Comparing Alibaba investment to Snapchat is simply absurd.
Yahoo made $9.4B on $BABA because of how revenue-driven their core businesses have always been.