AOL has offered something to it's members only for quite a few years called AOL Mall, where you can shop with various participating merchants that have signed on to their service, as if it was all one big online store.
You can buy from sites like Office Depot and Amazon.com right from the Mall page at the same time and it is all put into one big "AOL shopping cart" and all shipping info, etc is sent to the appropriate site at checkout. AOL handles the transactions and you get a detailed receipt of your purchases emailed to you and it is billed to your credit card or checking account (or even your phone bill if that is your pre-arranged payment method) when they bill you for your AOL account.
The whole Mall site is set up nicely with seasonal shopping articles and sites advertising their specials right on the front page. Like an article on home decorating would include items from a variety of participating merchants...you wouldn't have to wander all over the web to find all the stuff that goes together.
It's fully searchable for specific items and you can sort by price...much in the way Froogle can....great for comparison shopping.
They even have wishlists and the ability to be able to IM another AOL member the Mall page you are looking at so 2 people can shop together. And a gift suggestion feature where you can select "For Her", "For Him", "For Kids", "Under $50", etc.
The merchant list is a bit limited, but the ones they do have are the bigger more well known ones with a good reputation and not the little fly-by-nights that might attempt to rip you off.
I am sure the merchants that participate pay a fee to AOL to be included and AOL probably gets a percentage of all transactions they handle for their merchants.
Now if Google made something like that available and incorporated it into Froogle, that would be very cool.