You can use Filters to organize your mail. Yahoo! Mail Filters don’t block mail, they steer messages as they arrive into different folders.

To set up a new filter, click Options in the upper right corner of your Mail page. Under “Management”, click Filters. Click Add, give the filter a name, and choose from a variety of options to automatically direct certain messages into a specific folder. For example, send any messages you get from your family into a folder called “Family”. Handy! When you’re done, click Add Filter.