Within the last couple months, Windows Live and Google both released Custom Search services. I came up with a quick breakdown of both services shown below:
Google Co-op
- http://www.google.com/coop/cse/marker. With the Google Marker, you can add urls directly to your custom searches as you come across useful and relevant domains.
- There is a "Make Money" link where you link with your Google AdSense account.
- The advanced section is slightly more technical. It allows you to edit your custom search in xml format.
- script to embed the custom search textbox into your website.
- Google's portal to showcase custom searches: http://google.com/coop/cse/examples/GooglePicks
The Google Custom Search Team blog can be found at: http://googlecustomsearch.blogspot.com/.

Live Search Macros
Windows Live Search Macros can be found here: http://search.live.com/macros/.
- Search Macros allow you to create simple logic from a set of keywords (i.e. feed:, inbody:, AND). It is analogous to the command line for live search services
- Appealing custom search presentation layer: (My custom search for my entries on GWB can be found at: http://search.live.com/macros/yowhann/geekswithblogyh
- Live's portal to showcase search macros: http://gallery.live.com/default.aspx?l=4
- Has both a Basic option & an Advanced option for creating custom searches
- Basic does not involve having to use macros
- Advanced is the command line/script version of creating your custom search
Both of these custom search services have their advantages. The hope is that domain experts create valuable custom searches for other users. Valuable custom searches that everyone can benefit from. An analogy to draw from would be user generated content. User Generated Search? For consumers, it is certainly interesting to see Search evolve into the user generated content world.
A reference to a blog entry for Google Custom Search can be found here
To date, there have been 11,155 macros created from a user base of 9,542 for Live Search Macros. Google Co-op did not make their numbers readily available on their site.
SUMMARY:
While I have to say that Live Search gets the nod in terms of usability and functionality in terms of creation of your custom search engine, the actual search experience itself (the results I get) is bit humbling.