Microsoft Indexing Service HOW-TO
A lot of web sites provide search capabilities, where you can simple type several words, press "Search" button, and you'll receive a list of pages which contains these words. It's simple. But how can you implement these features in your own web application? Yes, you have to use indexing service which will index your files or web pages. After that you can use full text search features.
There are a lot of solutions which allow you to provide this functionality in your application. One of them is Microsoft Indexing Service. It's part of Windows 2000 and later Windows versions. So, if you provide only Windows solutions (ASP.NET web application, Windows Forms application, etc.) you have to see this Microsoft's product.
On of the biggest goal of Indexing Service that it's totally free. You can use it without any restriction or additional licenses. I think that this is so big goal, because other indexing products cost a lot of money. If you develop small or middle project you don't want to pay thousands dollars for full text search tool.
If you will choose Indexing Service you should remember that it can index only file system. For example, you can't use it for indexing files which stored in your database. This is a big minus of Microsoft Indexing Service, but I believe that you will solve this limitation.