We improve the readability of a personal timeline by weaving multiple social contexts of tweets into a visualization. Our social contexts consist of three dimensions: community membership, key persons, and interesting tweets within a personal timeline. A person is often a member of several communities, such as a family, a class, or a team, simultaneously. We identify all communities that a user participates in. Labeling a tweet with a visual representation to indicate what community it belongs to can help readers to understand why the tweet is written, since different communities are likely to carry tweets in different contexts. We then discover key persons and interesting tweets within a personal timeline. Our prototype design demonstrates how three social contexts work together for visualizing a personal timeline.