connection speed (e.g. dial-up, broadband, mobile broadband, WI-FI)
browser (e.g. latest, and older versions)
PC Memory (e.g. cache, RAM).
server storage space
pages with too many scripts
website content (e.g. databases, file formats used for images, sound, video, animation, additional technologies such as AJAX, ActiveX).
secure socket layers (SSL)
use of passwords
legal considerations (e.g. Data Protection Act, Privacy and Electronic Communications Regulations, Computer Misuse Act).
viruses, trojans and worms
hackers (e.g. Adrian Lamo, Kevin Mitnick, MafiaBoy)
identity theft (e.g. Abraham Abdallah).