Copyright is the exclusive right of exploitation of the maker of a work of literature, science or art, including software. The design of your products or line of service can, as long as properly worked out and otherwise meeting the requirement that it has an original character and bears your personal signature, may enjoy copyright protection as a format, hence strengthening your intellectual rights alongside, for example, your brand and/or trade name. Copyright is governed by the Copyright Act 1912 and a number of treaties. Copyright comes about automatically as soon as a work is completed. Registration or notification that copyright is reserved is not necessary. The ©-symbol with the year of publication behind it merely shows who is claiming copyright and since when (whether that is really the case, though, is another question). Sometimes the copyright is held by someone other than the maker, usually the employer under so-called employer's copyright.
Copyright expires 70 years after the death of the maker of the work, but can be bequeathed. Copyright can also be transferred to someone else by way of a deed. If you want to keep your say about your work, you can - usually against payment of royalties - grant a (limited) right of use (licence). You then give permission for your work, within a certain context, to be duplicated and/or published. It is advisable to draw up the licence in writing as evidence. Finally: related to copyright law there are neighbouring rights. These relate to the work of performing artists, record producers and broadcasting organisations. Their rights are laid down in the Dutch Neighbouring Rights Act (WNR).