If a proposed application requires special hardware, software, or connectivity, and the teacher does not possess these requirements at home, or cannot easily borrow what is needed, he or she will have no option but to find the time at school to learn how to use it. Finding the time in an already busy schedule may be very difficult, at best. Applications which build upon existing skills, such as using e-mail, Usenet, or browsing the WWW, are ideal candidates. Realistic applications must be reliable. If a lesson has to grind to a halt because the hardware or software crashes and someone has to be found to fix it, or the connection to a remote site goes down, then the teacher is going to be much more wary in future about using it.
Reliability is an issue of trust.
If the teacher cannot trust the technology, it will not find favour in the classroom. Designers of realistic applications must address the pragmatic concerns arising from the limited availability of computers and time versus many students. Also, students typically have fairly poor keyboarding skills, and so it is often inefficient for them to key in information themselves. As well as being a huge source of information, the Internet is an invaluable outlet for publishing information. Constructivism places emphasis on engaging in real-world tasks, and a basic requirement in the real world is to be able to convey information to others in an understandable fashion.