Comment Likes
This feature is only accessible to users logged in to WordPress.com.

Data Used: In order to process a comment like, the following information is used: WordPress.com user ID/username (you must be logged in to use this feature), the local site-specific user ID (if the user is signed in to the site on which the like occurred), and a true/false data point that tells us if the user liked a specific comment. If you perform a like action from one of our mobile apps, some additional information is used to track the activity: IP address, user agent, timestamp of event, blog ID, browser language, country code, and device info.

Activity Tracked: Comment likes.

Contact Form
Data Used: If Akismet is enabled on the site, the contact form submission data — IP address, user agent, name, email address, website, and message — is submitted to the Akismet service (also owned by Automattic) for the sole purpose of spam checking. The actual submission data is stored in the database of the site on which it was submitted and is emailed directly to the owner of the form (i.e. the site author who published the page on which the contact form resides). This email will include the submitter’s IP address, timestamp, name, email address, website, and message.

Data Synced (?): Post and post meta data associated with a user’s contact form submission. If Akismet is enabled on the site, the IP address and user agent originally submitted with the comment are synced, as well, as they are stored in post meta.

Jetpack Comments
Data Used: Commenter’s name, email address, and site URL (if provided via the comment form), timestamp, and IP address. Additionally, a jetpack.wordpress.com IFrame receives the following data: WordPress.com blog ID attached to the site, ID of the post on which the comment is being submitted, commenter’s local user ID (if available), commenter’s local username (if available), commenter’s site URL (if available), MD5 hash of the commenter’s email address (if available), and the comment content. If Akismet (also owned by Automattic) is enabled on the site, the following information is sent to the service for the sole purpose of spam checking: commenter’s name, email address, site URL, IP address, and user agent.

Activity Tracked: The comment author’s name, email address, and site URL (if provided during the comment submission) are stored in cookies. Learn more about these cookies.

Data Synced (?): All data and metadata (see above) associated with comments. This includes the status of the comment and, if Akismet is enabled on the site, whether or not it was classified as spam by Akismet.

WordPress.com Stats
Data Used: IP address, WordPress.com user ID (if logged in), WordPress.com username (if logged in), user agent, visiting URL, referring URL, timestamp of event, browser language, country code. Important: The site owner does not have access to any of this information via this feature. For example, a site owner can see that a specific post has 285 views, but he/she cannot see which specific users/accounts viewed that post. Stats logs — containing visitor IP addresses and WordPress.com usernames (if available) — are retained by Automattic for 28 days and are used for the sole purpose of powering this feature.

Activity Tracked: Post and page views, video plays (if videos are hosted by WordPress.com), outbound link clicks, referring URLs and search engine terms, and country. When this module is enabled, Jetpack also tracks performance on each page load that includes the Javascript file used for tracking stats. This is exclusively for aggregate performance tracking across Jetpack sites in order to make sure that our plugin and code is not causing performance issues. This includes the tracking of page load times and resource loading duration (image files, Javascript files, CSS files, etc.). The site owner has the ability to force this feature to honor DNT settings of visitors. By default, DNT is currently not honored.