First Impressions of users with systems and websites

First impressions are made when meeting people as well as when a system is used for the first time. Like real first impressions, the first look and use of online and system environments is also as critical for it's ongoing success. People will rate a site very quickly.
When you look at something from the usability perspective of a first impression, consider,

1. usability - is it easy to use the first time, make sense to your users, fits with existing mental models that your users have
2. trust & reputation - your users need to feel confident that information is correct and reputable
3. purpose - your users must feel there is useful information, it could "close a sale", it inspires your users, does it meet user goals/tasks, it iscreditable/reputable/reliable/quality outcome
4. visually appealing - ie fit with the personality/persona of your users, people can pick up alot of subtle non verbal cue from visual presentation
   
5. visually matches the words or task focus eg
   if it's a travel site or system talk about destinations, adventures,
   if it's about style or luxury talk about aspirations, success, do not disclose price, consumerism
   if it's about value for money talk about clean lines, text, price, buy now
6. keep it consistent - if you are part of a chain of companies and people know this then if it is part of your plan re-use functionality, tools, look and feel so that people know what to expect. Otherwise use other well known models that people are already familiar with.
   

So the moral to the story is, first impressions are as important for systems and tools as they are with people, so make it count. If you don't deliver on what is stated then people are not happy and it takes alot to change their mind later.