The extension will transmit the following data to Instapaper (Instant Paper, Inc.) under the following conditions:

• Your Instapaper username and password, and browser information (HTTP headers, IP address) when you initially login to the extension, and when you actively use the extension (e.g. when saving or reading a web page with Instapaper).
• The complete contents (HTML DOM) of the current tab’s web page in the browser for the purposes of saving or formatting it when you actively use the extension (e.g. when saving or reading a web page with Instapaper).

Absolutely no data is sent without you first having interacted with the extension for a given web page.

All data is transmitted over an encrypted channel (HTTPS).

You can access, modify, and delete all transmitted data through the Instapaper web site.

Please see Instapaper’s Privacy Policy for more details.
https://www.instapaper.com/privacy