When Valve released this year's Dota 2 Compendium players who purchased the ticket package were promised a variety of rewards of certain stretch goals were met. Having blown past every one of the stretch goals, and the extended goals (all the way up to $10 million), Compendium owners were wondering when to expect their items. That question was answered by the Overflowing Compendium Update, which includes a variety of Compendium rewards, such as the Pudgling Courier, weather effects, and chat emoticons. If you are a Dota 2 fan who still hasn't purchased the Compendium remember that even if you buy one now you still get all past and future rewards.
The Compendium continues to be one of the best $10 I have ever spent, giving me not only Hero items but also cosmetic items for the world and even the chat. Emoticons are my favorite addition so far, and I probably won't stop spamming the facepalming WindRunner in all chat.
Source: blog.dota2.com