Attention Yahoo! This is what My Yahoo! should be (instead of a lame news portal thing like everyone else): allow people to aggregate their bookmarks in their own personal Yahoo! hierarchy. Yahoo!, first and foremost, is a tool for people to find sites that they want to go to. More often than not, people go back to the places they’ve already visited, so why not keep track of that for them. Then think of all the analysis you could do on that data to suggest sites to users based on popularity and build a better general Yahoo! directory. Companies like Backflip are trying to do similar things, but a company like Yahoo! with millions of users and a database of millions of sites already in place could really offer something useful.