Find custom textin pagesource

This can be done in many ways, this is one of them
Create a windows application and add webbrowser[^] control to it.
Load the url and query the element from the DOM to read the text and write it into a text file[^]

Simple example: it will save your name to the text file, by passing this question url to it.

using System;
using System.IO;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{

    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            string url = "http://www.codeproject.com/Questions/1121032/Find-custom-textin-pagesource";
            WebBrowser web = new WebBrowser();
            web.Url = new Uri(url);
            web.DocumentCompleted += web_DocumentCompleted;
        }

        void web_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
        {
            WebBrowser web = (sender as WebBrowser);
            string name = web.Document.GetElementById("ctl00_ctl00_MC_AMC_QuestionAuthorRepInfo_MemberName").InnerText;
            MessageBox.Show(name);

            string path = @"D\yourFile.txt";
            if (!File.Exists(path))
                using (StreamWriter sw = File.CreateText(path))
                    sw.WriteLine(name);
        }
    }
}