The question is what is the "hottest extension", well that does not have to mean .com, that is the best. As for hot then I would suggest checking up Name Pros forum for "short extensions" and see what is HoT right now, it could be .com. it could be .org?
Top domain name extenxions on the world wide web: .com : Commercial .net : Networks .org : Organisations .edu : Educational .gov : US Government .int : International Organisations .mil : US Dept of Defense .pro : Professionals .biz : Businesses .info : Informational .com is by far the greatest for many reasons. But .net and .org are going very well lately. Check out all the .net sales in this weeks DNJournal. Many .net and .org domains have sold for $xx,xxx to low $xxx,xxx recently. With the right premium keywords, there are still nice sales to make in the lesser quality extensions (ex. JobsOnline.info sold recently for low $xx,xxx).
The top 3 are .com, .net & .org. The others? Crap? Please don't make a general statement if you have no experience in the other domains. I have written a lot about domains - google "ainuddin mohamad domain names" - and have several websites featuring expired domain names.
COM is the most recognised by a country mile and will be for the forseeable future. ORG is pretty much established as the extension of choice for charities and non-profit companies. As for all other extensions, opinion is varied. I would say it comes down to how you use the extension. Some extensions are easier to make good domains with than others. Even those that aren't great for making good domain names still have the potential to throw up decent ones - del.icio.us is a perfect example. Then there's the whole buzz about ME domains with insure.me and other similar domains on that extension. Even BIZ and INFO domains can be used to create great website names, as can AM, TV, etc etc
I agree with you because many of my websites with .info, .us, .cn, etc. domains are doing equally good. Earlier I had written