Microsoft actually offered a great deal to buy Yahoo a while back, but stupid leadership cheated all us shareholders. So Yahoo shouldn't even exist at this point...
Microsoft offered $31 a share in 2008. It's at $45 now.
The S&P 500 total return index has gone from 1330 to 2081 in the same time frame. So if Microsoft had paid you $31 dollars a share and you had reinvested it in the market, it would be worth $48.5 or thereabouts. Even if it does catch up, it will have taken more than 7 years to do so.
Just for another number to look at, according to Wolfram Alpha, the $31 in 2008 would be ~$35 today when you adjust for inflation.
That's all because of alibaba. Yahoo would be worth around $80-$90 if they had sold to MSFT or may be even more as they wouldn't have sold part of alibaba share like marissamayer did last year or so. would have, could have.