InDomain Search: (min 4 chars.)
Find your competitors. Example: if you sell boats, a domain query for 'boats' will find WordPress sites with 'boats' in their domain name. From there you can link to them, follow them on Twitter, contact them, get a link from them, negotiate with them and check out their Version, Theme, and Plugins.
You can NOT do this with Google.

InVersion Search: (digit dot digit)
You can see who's running an older version of WordPress. For example, enter any exact version number, such as, '4.5' and see the domains, themes, and their plugins!
You can NOT do this with Google.

InTheme Search: (min 4 chars.)
Many WordPress sites that are selling something use a theme made for their products. So, just like the domain name search for 'boats', if you search the themes for 'boats' you will see a list of those sites specializing in selling boats. Of course, you will also see their versions and their plugins.
You can NOT do this with Google.

InPlugin Search: (min 4 chars.)
Get a list of sites that are running a certain plugin. Example: search for 'slide' in order to find all plugins that are being used as image-slider type of plugins. So, when you want a slider plugin, you can search the WordPress.org directory or you can search here to see what others are using!
You can NOT do this with Google.

However, we believe they are overpriced. We have no competition! We could charge ANYTHING!

Just look at what they want to charge you:

Premium Membership (Beta Version) $19.95 Only: $4.95/month for the first 25 members! Up to 20,000 rows per query. 100 queries per day. Why is the price so low? Because we want to launch with a bang, Because this is the Beta version, (there will surely be a few glitches here and there), Because we run without a fancy air conditioned office. and because we run with a very small staff, me!