How do I?
You can add people to your 'reading list' as by clicking on their name or avatar to go to their 'my chow' profile. Then, when you go to your 'my chow' menu, you can see recent posts from those people using the 'Reading List' link.
You can add individual threads to your favorites list by using the 'Topic Options' menu that appears at the top of each thread. Those threads will then appear in the 'favorites' section of your 'my chow' menu, and you'll be able to see when they've been updated.
If you need more detailed instructions, ask away, and I can give you click by click.
-- Jacquilynne, Community Manager for Chowhound