If the ISP of posts can be traced by an external organization,
Then why was a website asked recently to disclose the identities of its anonymous posters (IIRC, it refused).
If the organization already knew the identities, it would not have had to ask.
Ping to my reply to piroque.
FReepmail if necessary.
Not so simple as that. In order to successfully use the identity information in a domestic criminal prosecution the information collected must have been collected in a way which can withstand the defense challenges regarding how evidence was collected. That leads to subpoenas, etc. to obtain records from the website, or ISP.
But other means exist for gathering data regarding IP addresses associated with addresses, and the IP addresses and content of packets traveling to and from a particular server. And it is very likely that some of those means are being used on a daily basis by organizations involved in security efforts.
So you should assume as a starting point that your identity can be determined by a number of organizations. Whether or not they care about what you post is another question entirely.