Microsoft Search Server 2010 – User Agent
If you wondering what is the default Microsoft Search Server 2010 User Agent it is: "Mozilla/4.0 (compatible; MSIE 4.01; Windows NT; MS Search 6.0 Robot)"
You can find it in registry entry: Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office Server\14.0\Search\Global\Gathering Manager\UserAgent
It is useful to know that if you want to hide part of the page from crawler - you can check visitor's user agent and if it is Search Server just not render that part.
Playing with Microsoft Search Server 2010 Express
Recently I was asked to find out if we can use new version of search server in one of our new projects together with the module we did develop to integrate it (Search Server 2008) with EPiServer.
I have started to search, investigating and I have few findings which I want to share here (mostly to have everything in one place 
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I have started with quick comparison of the 2008 and 2010 version - there is nice page that gives the overview what was introduced in new version. On that page you can find summary of new features introduced in version 2010.
Next thing I did was installing the Microsoft Search Server 2010 Express. The idea was to install it, try to crawl the page that was already using search server (but in version 2008) and try to just change the URL to the search web service. Of course there were some tricks to do it. For example I had error message when I wanted to crawl any page. I got the error: "Access is denied. Verify that either the Default Content Access Account has access to this repository, or add a crawl rule to crawl this repository. If the repository being crawled is a SharePoint repository, verify that the account you are using has "Full Read" permissions on the SharePoint Web Application being crawled." Luckily I found that post. Following the instructions from that post helped to solve it.
Good news is that it occurred that Query Search Schema of version 2010 is compatible with that one from version 2008. So the module we did develop to use it with Search Server 2008 is working with Search Server 2010 without changing single line in code
I am wondering if elements of search query SortByProperties and SortByProperty are finally working (they weren't with version 2008) 
When I will do anything more with new versions and I will have any interesting findings I will share it with you here