At its peak in 2000, Yahoo had a market value of $128 billion.
Bought Broadcast.com for $5.7 billion, bought Geocities for $3.6 billion
Yahoo agreed to buy Facebook for $1 billion, but the deal fell through when Yahoo tried to negotiate down the price. It passed on an offer to buy YouTube, and its purchase of eBay fell through because of clashing egos.
Microsoft's offer was actually $45 billion.
Yahoo bought Tumblr for $1.1 billion in 2013. It paid for it by selling 20% stake of it's 30% stake in Alibaba, the only thing it had that was making any money.