The past decade has seen healthcare costs rising faster than government expenditure in most developed countries. Various telehealth solutions have been proposed to make healthcare services more efficient and cost-effective. However, existing telehealth systems are focused on treating diseases instead of preventing them, suffer from high initial costs, lack extensibility, and do not address the social and psychological needs of patients. To address these shortcomings, we have employed a user-centred approach and leveraged Web 2.0 technologies to develop Healthcare4Life (HC4L), an online telehealth system targeted at seniors. In this paper, we report the results of a 6-week user study involving 43 seniors aged 60 and above. The results indicate that seniors welcome the opportunity of using online tools for managing their health, and that they are able to use such tools effectively. Functionalities should be tailored towards individual needs (health conditions). Users have strong opinions about the type of information they would like to submit and share. Social networking functionalities are desired, but should have a clear purpose such as social games or exchanging information, rather than broadcasting emotions and opinions. The study suggests that the system positively changes the attitude of users towards their health management, i.e. users realise that their health is not controlled by health professionals, but that they have the power to positively affect their well-being.