Advantage to having blog on separate domain?

[packerblitz]

Hi, from an SEO standpoint is there an advantage to having your blog on a different domain? For example, http://www.bhphotovideo.com/ has their blog located at http://www.bhinsights.com. Most companies would have it at http://www.bhphotovideo.com/blog. Is there a significant advantage to doing this with back links to your main e-commerce site?

Thanks!