I have seen "Official support for all Netscape client products ended on March 1st, 2008. Please see the announcement for more details." on top of the Netscape browser website. On their announcement they say to download the Mozilla Firefox web browser and seem they support on it.
I think the main reason behind this is huge drop of popularity on their browser. But anyway if you are interested on the Netscape Communications Corporation (now under AOL) and their activities and the history just click on the links below.