Is how easy it is to set up an alerting system to let you know of any documents that have been filed with Companies House by a company you may be interested in (e.g. one you either work for or have committed considerable personal investment with). It's a very useful way of discovering that a business has gone into administration (which can be a convenient way of avoiding paying smaller creditors). Go to
Companies House and then choose Webcheck, search for the company you're interested in and then when it provides the top level page, choose 'Monitor this company'. You need to register to use the service but it's free. Comes in handy sometimes when you get an alert to say that the company's registered office has just changed.