Get a contract!
The first thing that any self respecting business should offer their clients is a contract in which it clearly states the terms and conditions of the web development project. If your website contains any custom built software (e-commerce, property management, content management, etc.) this contract should come hand in hand with a design specification... this is a document that defines the exact perimeters of the software.
Your domain name.
Most web development companies will offer to register a domain name on your behalf. This is perfectly fine provided that it specifies in the contract terms and conditions that this domain name belongs to your company without reservation. Many web design companies will refuse to release a domain name they have registered on your behalf, or alternatively they will charge you a large "transfer fee" if you ever try to move it or gain any kind of direct control over it. This severely limits your options if you were to ever decide you weren't happy with the company currently managing your site.
Custom Built Software.
Many people are not as clued in about their rights when they buy software as perhaps they should be. If you are having bespoke software (bespoke software is a fancy way of saying "custom built") for your website and you are paying for bespoke software development then the contract between yourself and the software developer should specify that the software developed belongs to your company and should give you the right to edit, change or move your website to another provider without needing to contact the initial software developer.
Many companies pay out a fortune for bespoke development and only find out later that the software is only licensed to them and that they have absolutely no control over it. They are unable to move to another provider. They are unable to ask another software developer to make changes or modifications to the software. Their entire software package, website and all their data is being held to ransom by the company that initially created the software for them.
Pre Built Software.
Many web development companies offer pre-built software and/or web services, the source code for which they guard jealously. This is perfectly normal, but make sure that you are happy to use a piece of software over which you have no control and read the small print carefully to make sure that you are at least the legal owner of any data collected by said software.
Alternatively find a web development company that is willing to give you a copy of the source code when you purchase a pre-built software solution. I for one have always believed in the consumer's right to move to another developer when changes or fixes need to be made to any software. Whether this decision is geographical, financial or you are simply no longer happy with the services your web development company provides makes no difference.
With the recent explosion of web based software and the convenience which this offers to consumers, it is no surprise that many people opt for this type of software when setting up their companies. If you are planning on getting some web based software developed, beware... not all developers are as generous as they would have you believe.
Third Rock Design