Extract text from pdf and word files

You can use the filters designed for / used by the indexing service. They're designed to extract the plain text out of various documents, which is useful for searching inside a document. You can use it for Office files, PDFs, HTML and so on, basically any file type that has a filter. The only downside is that you have to install these filters on the server, so if you don't have direct access to the server this may not be possible. Some filters come pre-installed with Windows, but some, like PDF, you have to install yourself. For a C# implementation check out this article: Using IFilter in C#

PDF:

You have various options.

pdftotext:
Download the XPDF utilities. In the .zip file there are various commandline utilities. One is pdftotext(.exe). It can extract all text content from a well-behaving PDF file. Type pdftotext -help to learn about some if its commandline parameters.

Ghostscript:
Install the latest version of Ghostscript (v.8.71). Ghostscript is a PostScript- and PDF-interpreter. You can use it to extract text from a PDF as well:

gswin32c.exe ^
 -q ^
 -sFONTPATH=c:/windows/fonts ^
 -dNODISPLAY ^
 -dSAFER ^
 -dDELAYBIND ^
 -dWRITESYSTEMDICT ^
 -dSIMPLE ^
 -f ps2ascii.ps ^
 -dFirstPage=3 ^
 -dLastPage=7 ^
 input.pdf ^
 -dQUIET 

This will output text contained on pages 3-7 of input.pdf to stdout. You can redirect this to a file by appending > /path/to/output.txt to the command. (Check to make sure that the PostScript utility program ps2ascii.ps is present in your Ghostscript's lib subdirectory.)

If you omit the -dSIMPLE parameter, the text output will be guessing line breaks and word spacings. For details look at the comments inside the ps2ascii.ps file itself. You can even replace that param with -dCOMPLEX for gaining additional text formatting info.