livecanvas

The Purpose: allowing your users to search differently
Ajaxed search engines are all over the place ? literally. 
Whenever a large amount of items is available, be it houses for rent 
or computer spare parts, providing your users with a fast, structured, faceted search 
can be one thousand times more efficient, rather than letting your visitors sink into hundreds of web pages, 
hoping they?ll find what they need ? almost by chance. 
This tool does not replace or try to extend the build in textual search feature of WordPress; 
it aims to provide a quick bootstrap to an ajaxed search engine, demonstrating how easy it can be to turn 
your website into a powerful search tool, without installing a huge and bloated code.
It is easy to hack and to extend at your will. 
You can read here the original article about why <a href="http://www.dopewp.com/searchy/" rel="nofollow ugc">Searchy</a> was built.
<h3>Main Features</h3>
Let your users search combining different criterias: Filter by name, category, tag, or custom field (=1). 
Sort results by date, name or custom field (numeric)
<h3>Typical usage</h3>
Searchy is a customizable search engine composed of two elements: the search filters – typically a filters column, and the search results.
Use the searchy_filter shortcode or the built-in widget to show the filters column. 
Place the searchy_results shortcode in a WordPress page to show the sort bar and the search results. 
Of course those go in square brackets in a chosen Page. 
You can place them one after the other, having searchy_filter and searchy_results close, 
Or get fancy building your custom layout, placing some do_shortcode calls wherever you want.

Searchy

An AJAX Search Engine allowing different criterias for sorting and filtering your posts. Use via simple shortcodes and few settings.

mattwalters

WordPress Filter is a comprehensive post filtering & template system. It allows the user to define a set of simple “Catches” (criteria) to be met by a post, and then have a set of “Actions” applied to the post. This plugin takes action whenever a Post is published inside of WordPress (including Posts coming in via XMLRPC). It can be used for many tasks, including creating your own mini plugins without ever having to leave your WordPress administration area.
v1.4
Added some catches back in (particularly Post Status which folks had been asking for). Sorry it took me so long for a new release to be ready.
Added:
<ul>
<li>Catch – Post Author: Equals</li>
<li>
Catch – Post Status: Equals
</li>
<li>
Action – Post Status: Equals
</li>
</ul>
Changed:
<ul>
<li>Catches like “Post Title: Equals” no longer case sensitive</li>
</ul>
Bug Fixes:
<ul>
<li>Fixed image link on add filter screen</li>
<li>Fixed issue where if looking for content within the Post Content, Excerpt or Title and the content is the first string, it would not realize it was found (for instance if looking for “Hello” and the text being searched was “Hello world”, the plugin catch would not engage)</li>
</ul>
Coming In Future Version:
<ul>
<li>Ability to run one-off filters. Basically you’ll be able to define a filter and then run it on all of your current posts.</li>
<li>Ability to force a filter to run on a post even if that specific filter has already been run on the post.</li>
</ul>
<h3>Example Usage</h3>
Let’s assume you want to participate in <a href="http://photojojo.com/content/tutorials/project-365-take-a-photo-a-day/" rel="nofollow ugc">Project 365</a> but want to make it as easy as possible. You would like to take a picture with your camera phone and send it to your flickr2blog email address with the title “potd”. To do this, you could use WordPress Filter in this way:
Define the Catch:
<ul>
<li>If Post Title: Equals “potd”</li>
</ul>
Apply the Actions:
<ul>
<li>Title: Replace “Picture of the Day”</li>
<li>Tag(s): Add “potd_%%year%%, photo”</li>
<li>Content: Append “ This photo is part of my <a href=”/tags/potd/”>Picture of the Day Series for %%year%%</a>.”</li>
</ul>
When the post arrives at your blog it would:
<ul>
<li>Change the post title to “Picture of the Day”</li>
<li>Add the tags “potd_2008, photo”</li>
<li>Add a short bit of text to the end of the content</li>
</ul>
%%year%% is a substitution that will be made by WordPress Filter at the time the post is saved. It inserts the current four digit year. There are other System Substitutions (see Other Notes tab for a listing) as well.
Another good use for this plugin would be to auto-tag or auto-categorize your posts. For instance, you could set it up so that whenever you mentioned “Microsoft” in a post, you could have it automatically categorize the post in “Technology” and tag the post with “technology, microsoft”.
<h3>System Substitutions</h3>
<ul>
<li>%%day-num%% -> Current day of the month in numeric format (1, 2, 3, etc)</li>
<li>%%day-text%% -> Current day of the month in text format (Monday, Tuesday, etc)</li>
<li>%%year%% -> Current four digit year (2008, 2009, etc)</li>
<li>%%month-num%% -> Current month in numeric format (1, 2, 3, etc)</li>
<li>%%month-text%% -> Current month of the year in text format (January, February, etc)</li>
</ul>
<h3>Support</h3>
Please use the <a href="http://code.google.com/p/wordpress-filter/issues/list" rel="nofollow ugc">Issues Page</a> to report bugs and request feature enhancements.

WordPress Filter

WordPress Filter is a comprehensive post filtering & template system. It allows the user to define a set of simple "Catches" (criteria)  …

Searchy vs WordPress Filter