A Google Webmasters Help thread has a webmaster upset that he lost his rankings in Google. He switched web hosting companies and days later, his Google rankings plummeted. On typical server move, you should not really lose rankings, if done right. But this person lost his/her rankings.
Google's JohnMu chimed in on the thread, saying:
It looks like your site might have shown a generic server start page for a while (a "This is the default ... server page. (...)" page). When this happens over a few crawls, it can confuse Googlebot enough to cause problems with the indexing of your pages. At the moment it appears that this is no longer happening, so I imagine it'll just resolve itself automatically over time.
Good news, the rankings should come back. But I noticed an interesting tweet from @JohnMu saying:
Tip of the day: If you have a generic "your site will be hosted here soon" page, use "noindex" or 503 result code, thanks!
Clearly that is related to this post. This is a good tip for anyone who is moving or setting up a site. I would completely avoid showing a generic message on the server, if possible, but if you can't, the advice above makes sense.
If you want to see a live site with one of these starter pages, see http://commgrad.uky.edu/.
Forum discussion at Google Webmasters Help.