Click on the catalogue record of an item you like, for example Mister Pip and scroll down to Community Activity. Here you will see ‘Comments, Summaries, Quotes, Notices, Age, Videos’. Click on ‘Comments’, or any other heading that someone has added to, then click on a username to see other titles on that person’s ‘completed shelf’.
If you want to ‘follow’ another user, click on the green ‘+’ below the main red heading. You can choose to ‘follow’ everything, or just certain types of items.
If you choose to make items on your own shelves public, other people will be able to follow you also.
For more info on ‘following’, check the FAQ panel to the right of a user’s ‘completed shelf’ page.