This post has been long overdue on my part. I have been planning to write this up for now over a year...

Windows Live Spaces search feature is a very powerful tool that allows you to to search Spaces contents in a very precise way. Let me first introduce some basic concepts:

Scoping (a.ka. Drill down): Spaces search results can be scoped to specific object types. Currently, 4 types of scoping is permitted: "All", "Spaces", "People" and "Blog entries". The following image shows the various options.

When you first do a keyword search (more on this below), we try to give you a "preview" into all areas of Spaces that would have a match for your given search term. From here you can narrow down (aka drill down) into one specific area that interests you. For example, if you are just looking for personal spaces home page (e.g. nikhil.spaces.live.com), narrowing down to Spaces is what you would do. On the same idea, if you are looking for profiles (e.g. http://nikhil.spaces.live.com/personalspace.aspx?_c01_memberprofiletile=showdefault&_c=memberprofiletile), you would select "People" and if your interest lies in blog entries (e.g. http://nikhil.spaces.live.com/blog/cns!A6E2B32DB60BF014!925.entry), you would use "Blog entries" scope.

There are 2 ways to drill down to your specific scope (or result type) - By using the drop down box (as shown in the above image) or by clicking the name in the section display (see image below).

Search Types: Now that we have some understanding of what scoping is and how it works, let's change our focus on different types of searches that Spaces supports. The first type is very obvious - Keyword search. This is the search that happens when you issue a search query from the Header (sorry for the squished up image).

Keyword search is what you would generally do on MSN Search (or Google). When you do a keyword search, the page text crawled is searched. Also, for a keyword search, you can scope to all different types of searches.

The second type of search you can do is "Interests" or "Tag" search. This is a very specific search that you can initiate from various UI elements - From the "Spaces interests" page, or from the interests section of a personal profile page or from "Advanced People Search" (more on this one below). When you do an "Interests" search, we (Spaces) issues a special "META" search for people's profiles that have been "tagged" with those interests. As we are searching for interests, we only show you "Profile" scoped results.

The third type of search is the most advanced, complicated and well, interesting. We call it Advanced People Search or APS for short. You can do an APS from the Spaces home page.

This is again a people profile search so you would get only "People" results and you cannot change the scope. This is a specialized search that searches for people's profiles for very specific items. You can search for Display Name, First Name, Last Name, Gender, Age range, Location, Occupation and Interests or any combination there of. This allows you to search for, lets say, Females, in the age range of 25-29, living in Seattle, who are software engineers and are interested in having fun :-). This is a very powerful search mechanism that let's you drill down on very specific attributes for people you are looking for.

Other UI elements:

• Saved session search: Once you have issued a search, it will be saved for your session and you can always visit it back by clicking on the "Search" tab on the left navigation panel on the Spaces home page.

• Contact control: Spaces search is very different than other search engines as we do not show you just the search results. For each search result, we show you a "Contact control" which allows you to see that person's photo (if available) and a bunch of other options like viewing their space, profile, contact card, friends list, etc. etc.

• "Safe" search: We take protecting our minors very seriously. Only "gray area" words are allowed if you are signed in and are of an adult age as defined by your market (for example 18 years in en-US).
• Search RSS feed: Spaces search results are also available as RSS feeds (if you are so inclined). Navigate down to the bottom of the page and you will see a cool looking RSS icon which will let you subscribe to that search result (properly scoped and typed) as an RSS feed. We limit the RSS feed items to the top 10 items.

• "Collapsible" sections: The search results for each scope are contained within a section which can be collapsed/expanded by either clicking the +/- symbol on the left or on the blue section header.

• Ads: Of course, we have to make money too :-)

What sucks: Aha... The section that every developer hates to talk about. But I will be brave and hopefully you will also be understanding enough as we work through the issues and improve the experience. My 2 biggest sore points are result count and  paging controls. We are working on both these issues and hopefully will have a better story on them.

• Result count: Although we show that for a given query we have 137838 results (see image above), we do not show any results over page 16 (or 17). Basically, we cap out at 250 results (we are not responsible for this - more on this in another post). It SUCKS.
• Paging: This is a direct result of the above problem. The paging model allows you to navigate to the "last" page of search results, but since we cap the result as 250, this paging model does not make sense.

Hopefully, these notes would help you understand how spaces search cab be used by you in a more meaningful way that relates more to what you are looking for. After all, Windows Live Spaces is your personal reflection to the world.