They've done a lot, like rolling out new updates to Yahoo Mail (where they can serve ads like Gmail) and other monetization things like offering prints for Flickr. Only time will tell if it will be successful. There are rumors that Safari on iOS will default to Yahoo, and that may help turn the numbers around a bit.
I would like to see Yahoo on iOS (even tho I don't use it), because I want to see Google to have a competitor. And in the last few years Google is getting stronger and stronger. I hope Yahoo gets a chance.
