aprs.fi will join Wikipedia and Reddit, and protest the proposed U.S. SOPA/PROTECT-IP legislation by closing down on Wednesday.
The aprs.fi outage will only affect clients in the United States (or those with IP address mapping an U.S. network operator – the targeting is not fully accurate).
Although the law is being made in the U.S., it will break the Internet on a global scale by making sites such as aprs.fi liable for links and content posted by the users of the site. Sites like aprs.fi are commonly run by individual developers or small volunteer teams. Due to the huge volume of automatically published user-generated content (50 packets per second currently!) it would be impossible for me to go through it all before publishing. If some APRS user would post links to copyright-infringing material, even when that material would reside somewhere else than aprs.fi itself, aprs.fi could be shut down in the U.S. and there would not be much that I could do about it.