MSN has refused to confirm whether it is censoring messages sent across the MSN Messenger network.

Computeractive tried sending messages containing the phrase download.php, as might be found in a web link. Although the message appeared to have been sent, the recipient never got it. There was no warning on the sender's PC, as might happen if someone was sending a picture to a computer that cannot receive it.

In a statement, MSN said that it had added a security feature to MSN Messenger to prevent users from accidentally clicking on links sent in messages but said nothing about whether the messages would be blocked.

A spokesperson for AOL said that AOL Instant Messenger (AIM) does not censor messages sent over the AIM network. A quick test in the office confirmed this.