Chrome: If you do a lot of shopping online, then you know it's easy to lose track of an item unless you hit the buy button right away. Impulse is a Chrome extension that allows you to drop any product image from any store into a personalised shopping cart.
Functionally, it's not much different then setting up a bunch of bookmarks, but it makes organising your shopping a little easier. Impulse sits on the side of the screen, and when you drag a product image over it, it adds it to one of your lists. You can keep running lists for yourself, gifts or anything else you need. If you hit up different online shops and want a consolidated wish list or price comparison list, then Impulse is a handy extension.