A few years ago, Lexicon Branding, one of the naming firms where I worked, researched perceptions of .com, .net and .biz top-level domain names.
The research found that .coms are, in the abstract, perceived more positively over the lesser-used .biz (et al) domains. This is not surprising: Familiarity breeds trust.
But that's today. The non-.com domains will eventually become more widespread and familiar as companies struggle and fail to find great .com names. The roster of today's bad web names goes on and on; companies compromise their name and ultimately their success just to secure a .com.
That's unwise. The Lexicon research also revealed that people's perceptions of an actual website did not differ no matter what its top-level domain. So in the end, the top-level domain doesn't change perceptions.
Dot com is already losing relevance. The strength of search engines like Google makes finding companies by their name, not their domain name, easy. As a name developer, I welcome the day that the tipping point finally comes when .com top-level domains are no more special than .net, .biz, or whatever others ICANN ordains.
There was a time when only a 1-800 indicated a toll-free telephone number. Now, there are many and they are readily accepted.
The same will hold true for top-level domains.