While some users might question the reason to transmit some of the data, for example the number of active users, the reason for transmitting it is to make sure that no plugin or add-on is in use that is on the global ban list. This list contains only five plugins and add-ons currently but it seems to be a way to prevent harm to the products if the user decides to install malicious products.

The five plugins and add-ons that are currently on the blocklist are:

• Internet Download Manager, v2.1-3.3 for Firefox 3.0a1 and newer (see bug 382356).
• Free Download Manager, v1.0-1.3.1 for Firefox 3.0a1 and newer (see bug 408445).
• Yahoo Application State Plugin, v1.0.0.5 and older for Firefox 3.0a1 and newer (see bug 419127).
• Vietnamese Language Pack, v2.0 for all applications (see bug 432406).
• npLegitCheckPlugin.dll, for Firefox 3.0a1 and newer (see bug 423592).

It is possible to disable this feature by setting the extensions.blocklist.enabled to false in the about:config dialog. I would not advise to disable the feature though unless you are sure what you are doing. The Mozilla team may block plugins and add-ons that are installed on your system using that option. If it is disabled this is not possible.