Here's why you should always blog under your own domain name, and never use a subdomain under one of the popular blog services: They could take the name away from you at any time, as one Tumblr user found
when his blog was displaced to give his URL to Pitchfork. Lame. Of course, even if you do use your own domain, that might not stop Tumblr from deleting your blog
, but you could then at least resurrect it elsewhere.