The people behind the site apparently claim that the index is legal because they will not make any profit from the site. The old site, in case you hadn't guessed, made its money from advertising click-through.
Despite the ads on the old site, Releases4U was popular because its index links were verified by the site operator and updated by the users.
The principle is similar to VCDQuality, except that, unlike VCDQuality, the indexes route straight through to eDonkey compatible download sources.
The Dutch anti-piracy authorities, meanwhile, are reported to be less than pleased with the re-opening of the Releases4U portal and will be taking action shortly...