QUOTE(dekyto @ Nov 8 2010, 11:57 AM)
In reading through this post I think that I am having a similar situation.
For years we have ranked at the top for 'Christmas Wreaths' the site is www.artificialchristmaswreaths.com
The title tag has been displayed as long as I can remember:
<title>BEAUTIFUL CHRISTMAS WREATHS by Artificial Christmas Wreaths.com</title>
Within the past week Google, Yahoo!, and Bing have stopped showing the title tag and are showing:
Google : Artificial Christmas Wreaths
Yahoo!: Artificial Wreaths
Bing: Artificial Wreaths
First of all, your robots.txt file is blocking all crawlers. Why is that?
However, it also appears that you have a canonical issue that may be related to the problem. Keep in mind that even though this might not have caused issues in the past, the search engines can and do change the way they do things all the time.
Your internal links for your root URL (home page) point to your HTTPS domain + "index.html", which is indexed in Google with the correct title. But when people search on your site, Google shows the root URL with a title (presumably) of its own design/extraction.
I don't see a listing for your site in Bing, except for the blog (which actually has the title "Artificial Christmas Wreaths" and displays properly) and a deep content page. UNLESS I search on the domain name. I think Bing has only partially indexed your site and they are probably using link anchor text from other sites to give your URL a title of "artificial wreaths".
Bing is pickier than Google and it's often more challenging to get Bing to index a site properly. You have to obtain links from sites that Bing indexes, and you appear to have done that, but for some reason Bing is not grabbing your content. Perhaps it's related to the canonical problem I mention above.
NOTE: I'm getting inconsistent hits on HTTPS vs HTTP for your site. I can definitely load the same content from both protocols.