The product list / mass update form lists all products in a category with the ability to update price, stock number, category, active/inactive and deleted on all products in the category. This form is especially useful when moving products.
Choose Category: This dropdown allows you to change the category you are currently viewing
Sort: This changes the sort order of the item in the category
Name: Click on the name of the item will launch the product edit screen where you can perform all product edits.
Price: Update the main price of the item
Stock #: Update the stock number of the product
Category: Move this product to another category
Type: Main = This is this product's main category. Related = This item is in this category as related. (See the product edit tab related products/categories for more information)
Helpful Hint: This product screen is also how search results are displayed. So for example if I wanted to move every product that had the word "blue" in its title, I would search for "blue" and then update all the categories.