Rapisahre.com was down for a couple of hours and there was no official announcement by the rapidshare staff. Some of  the ISPs block rapidshare to make better use of their bandwidth, because all these file sharing sites have 60-70% of  illegal stuff (as far as I have seen). All those blackhat-under-world websites and the people sharing copyrighted material use such website.
 
While the downtime, it was giving an impressions that rapidshare has been shut down by the authorities, as stated on the Wikipedia
 
On 19 January 2007, news broke that German collections agency GEMA had claimed to have won a temporary injunction against both RapidShare.de and RapidShare.com. “The latter is said to have used copyright protected works of GEMA members in an unlawful fashion,”.[4]To date RapidShare has claimed not to have any knowledge of the content uploaded by the users and of not being in a position to control the content. Through its injunctions the District Court in Cologne had now however made it clear to the company that the fact that it was the users and not the operator of the services that uploaded the content onto the sites did not, from a legal point of view, lessen the operator’s liability for copyright infringements that occurred within the context of the services, the spokesman added.
 
I personally believe there should be some sort of legal action against website hosting copyrighted material and such websites MUST be shut down.