I had a server crash and no backup. Killed all of my 30 sites. I want to keep the domains and build the new sites on a different server. These sites will be brand new. Will Google penalize me, when it can not find all of the old post url's that have already been indexed? Approx 20,000 posts, combined between all of the old sites. I just want to start over from scratch on all of the domain names, and I want to know if it will be worth the effort. Thanks for any input from those with plenty of experience in this area.
I don't know what will happen to your site rank, but here's my story. I have one PR 2 domain, one day i have no time to update or just think about my blog(s), even my web hosting invoice, and then about 8 months after that i realize that my site and of course with the content is gone because i didn't pay the invoice, my pagerank was dropped from 2 to 0. I don't know what to do, just like your condition now, if i want to collect my content then google cache is my only hope, but it such a hard thing because it isn't easy to collect lots of post and pages in google, so i decide to build a new site with the same domain but totally different content, and about few weeks my pagerank is back