Google blogsearch offers some of the default google search operators and other less-known operators. Here they are, with some tips and a wordpress hack :)

Oh, as always, google is a little nervous when using advanced search strings, so sometimes it returns a 404 not found… it’s just trying to display the well-known 403 because it finds the search a bit suspicious… but the page is missing…

link:

this is a standard google operator, but in blogsearch it really works, while in standard google it displays a small percentage of the known inbound links. Finally a way to discover inbound links without using yahoo or technorati!

inpostauthor:

search for the given string in post author.
Tip: This is a good reason to use your full name while posting, since google blogsearch indexes your name! If you want to gain visibility you should really avoid using a nickname! (well, I discovered this recently, so my posts can still be found searching for inpostauthor:”fra” … but this is going to change… this post should be found under inpostauthor:”francesco mapelli”)
Tip #2:The default wordpress rss-comments module does not use the <author> tag to describe the autor of the comments, so searching for inpostauthor:yourname returns just the blog posts… but if you hack wp-commensrss2.php adding

<author> <?php echo get_comment_author_rss()?> </author>

to the comments loop, for example before the <pubDate> tag, blogsearch will find also your comments.
If you want to test it, just write a comment in this post, wait for google blogsearch to read the rss (it’s very fast, something like ten minutes should be enough) an check with blogsearch!.
I think I’ll wirte a wordpress plugin for this.

update: since wordpress 2.1, the author is included by default in comments rss… there’s no need for this hack anymore :) 

inblogtitle:

search for the given string in blog title: inblogtitle:mapelli

inposttitle:

search for the given string in post title: inposttitle:google search guide

blogurl:

search for blogs with the given url: blogurl:http://www.mapelli.info/
 or for blogs under the given domain
doughnuts blogurl:wordpress.com searches for blogs talknig about doughnuts on wordpress.com