My Anime is a place where you can organize all the anime you have seen and want to see. You can
create custom lists of titles and DVDs
rate titles you've seen
add your comments
keep your lists private or make them public
look at other people's public lists for ideas of new anime to watch (or avoid!)
and do all that for manga too.
In order to use this feature you must be logged in. But you can get a feeling of what this feature offers by looking at other people's anime lists.