Google creates a tool for creating your own contextual search engine. And an addition tool to customize it incrementally. You can create your own, here.

You can customize it in two ways:

• By specifying a set of keywords
• By specifying a set of websites (the search can be limited to these sites or just used for emphasis)

There are a couple of nice features.

• Google Marker allows you to add sites to custom search engine easily. This way you can keep refining your search
• The keywords are used as hints to the search engine. I hope Google will use it simply as a way to establish context to your searches.
• You can allow others to contribute to this search.

I created one for XML for testing it. Works great. I will keep refining it.

Here are a couple of wish list items:

• A recommendation service where new related topics and sites are recommended from Googles database of searches
• An RSS stream for results
• More ways to customize search results

Here is the link to Google’s Blog Entry.