To improve your privacy in ubuntu just follow below steps.
STEP 1: Stop the collection of anonymous information.
To stop the collection of anonymous information in ubuntu
1.Click the ubuntu dash and type system settings and select System settings application.
2.Select the Security & Privacy menu from Personal.
3.Then select the Diagnostics tab.
4. Unselect Send error reports to Canonical and Send occasional system information to Canonical options.
STEP 2: Disable online search results in Ubuntu Dash
1.Click the ubuntu dash and type system settings and select System settings application.
2.Select the Security & Privacy menu from Personal.
3.Then select Search tab.
4.Turn Off the When searching in the Dash include online search results.
STEP 3: Disable recently used application and files list
1.Click the ubuntu dash and type system settings and select System settings application.
2.Select the Security & Privacy menu from Personal.
3.Then select Files & Applications tab.
4.OFF the Recrd files and application usage option.