Recommend something
On a topic, choose who to recommend it to and add a note: "You'll love this." Each friend is told and can add it to their plans. You can only recommend what they can see and do not already have.
Answer recommendations
Recommendations lists what friends sent you. Add one to a category of yours — it arrives as planned and remembers who suggested it — or set it aside. The friend is not told when you set one aside.
Compare tastes
On a friend's profile you can compare your taste with theirs: how much you agree on the titles you both rated, your closest calls and biggest disagreements, and what they loved that you have not tried. Scores on different scales are compared fairly.
Taste matching can be switched off under Privacy and data → Taste in settings.