I'm curious about how you time all of this. Do the 170 invitations get sent out simultaneously (Bar the manual captcha ones), or is it more staggered?
e.g. Could the big fish like Techcrunch and such expect to be notified first normally, or is it a blast to everyone?
I'm also curious what your plans are to keep your service's reputation with the bloggers on the receiving end intact (The fact it is paid for, and not too cheap, really helps this I imagine), but anything else you have in mind? e.g. Do yous do any kind of filtering of the submissions?