The difference is personalization. I never would visit a portal site like yahoo, but every morning I look through my Google Now feed. Relevance matters.
Yeah, I actually hated when that went away. I had several RSS feeds on there, my inbox, my calendar... never found a good replacement. I used Netvives for a while, but it was somehow not the same (can't really put my finger on it, though).
Except Google Now still completely sucks because you have close to zero direct control on what gets shown there.
Also: I like that they're experimenting, but come on. Replacing a settings menu with a list of very specific yes/no questions that are added to that list as you encounter them - that's just wrong. You don't even get a benefit of being able to scroll through a settings screen to discover what features are available...
After it went away I spent a lot of personal time building something similar on a unix box running at home. Still miss some of the features I could never replicate though.
It was my homepage for the longest time. Such a great service. Sadly now I have to come to HN and hope there's something of interest here when I have 15 minutes to spare.
You could actually customize excite.com a great deal. You could choose your stocks, your weather with a zipcode. You could make a box with your favorite links, you could drag around the various boxes and news feeds, add RSS links. The whole deal. It wasn't personalized content created automatically based on your search history though.