If my keywords are "My" and "Widget" and i can choose between 2 domain names: 1. mywidget.com 2. my-widget.com which is better for SEO? Thanks, Frank Commodity Trading Software
2. my-widget.com, particularly if "my widget" is your main keyphrase. This is because your key phrase will be in the anchor text in any inbound link of the form <a href="http://www.my-widget.com>www.my-widget.com</a> which is the way that many unsolicited links are constructed. - Michael
I agree with the above, but I'll add that for Google it doesn't really make a big difference as long as the page/site is optimised for those 2 keywords/1 keyphrase (you might want to register both, at some stage). So: go for the dash (it might also be much more readable!)