Seo Helper Class

SeoHelper.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;

public static class SeoHelper
{
    public static string[] GetKeywords(string input, bool cultureInvariant)
    {
        RegexOptions options = RegexOptions.CultureInvariant | RegexOptions.Compiled;

        if (!cultureInvariant)
            options = RegexOptions.Compiled;
        var matches = Regex.Matches(input, "[\\w]+", options);

        if (matches == null)
            return null;

        var segments = new string[matches.Count];
        for (int i = 0; i < matches.Count; i++)
        {
            segments[i] = matches[i].Value;
        }

        return segments;
    }

    public static string MakeValidUrl(string input, bool cultureInvariant)
    {
        if (input == null)
            return null;

        var keywords = GetKeywords(input, cultureInvariant);

        return string.Join("-", keywords);
    }

    public static string[] GenerateKeywordsFromText(string input, int count, bool cultureInvariant)
    {
        if (input == null)
            return null;

        var keywords = GetKeywords(input, cultureInvariant);

        if (keywords == null || keywords.Length == 0)
            return null;

        var groups = (
                            from word in keywords
                                    group word by word into g
                                    select new {Word = g.Key, Count = g.Count() }
                        );
			
        return groups.OrderByDescending((f) => f.Count).Take(count).Select((f) => f.Word).ToArray();
    }
}