UPDATE 05/01/2010:  Per Donovan Olivier's Suggestion, I've updated this widget to fix a problem in displaying Twitter usernames with an underscore in them.  Thanks Donovan!

I made some tweaks today to the new Twitter Widget that was released with BlogEngine.NET 1.6.  I noticed that @User and #Hash tags were not linked up, so I fixed that.

Below is the code you need to modify.  Any GREEN code is new, any BLACK code is code that was already there.  Should be pretty easy to cut/paste it in place.

Option #1: Download the version 1.1 widget.ascx.cs-v1.1.zip (2.90 kb) file directly, drop it into your site, refresh.

Option #2: Make the following changes in the file: <root>/Widgets/Twitter/widget.ascx.cs:

Comment this out, or remove it all-together:

//if (title.Contains("@"))
//    continue;

Add the two lines shown here:

twit.Title = ResolveLinks(title);
twit.Title = ResolveUserLinks(twit.Title);
twit.Title = ResolveHashLinks(twit.Title);

Add the green lines below:

    //URL
    private static readonly Regex regex = new Regex("((http://|https://|www\\.)([A-Z0-9.\\-]{1,})\\.[0-9A-Z?;~&\\(\\)#,=\\-_\\./\\+]{2,})", RegexOptions.Compiled | RegexOptions.IgnoreCase);
    private const string link = "<a href=\"{0}{1}\" rel=\"nofollow\">{1}</a>";
    //@User
    private static readonly Regex regex2 = new Regex("@[a-zA-Z0-9_]*", RegexOptions.Compiled | RegexOptions.IgnoreCase);
    private const string link2 = "<a href=\"{0}{1}\" rel=\"nofollow\">{2}</a>";
    //#Hash
    private static readonly Regex regex3 = new Regex("#[a-zA-Z0-9]*", RegexOptions.Compiled | RegexOptions.IgnoreCase);
    private const string link3 = "<a href=\"{0}{1}\" rel=\"nofollow\">{2}</a>";

Add the two green functions below:

    /// <summary>
    /// The event handler that is triggered every time a comment is served to a client.
    /// </summary>
    private string ResolveLinks(string body)
    {
        return regex.Replace(body, new MatchEvaluator(Evaluator));
    }
    private string ResolveUserLinks(string body)
    {
        return regex2.Replace(body, new MatchEvaluator(EvaluatorUser));       
    }
    private string ResolveHashLinks(string body)
    {
        return regex3.Replace(body, new MatchEvaluator(EvaluatorHash));
    }

    /// <summary>
    /// Evaluates the replacement for each link match.
    /// </summary>
    public string Evaluator(Match match)
    {
        CultureInfo info = CultureInfo.InvariantCulture;
        if (!match.Value.Contains("://"))
        {
            return string.Format(info, link, "http://", match.Value);
        }
        else
        {
            return string.Format(info, link, string.Empty, match.Value);
        }
    }
    /// <summary>
    /// Evaluates the replacement for each @User link match.
    /// </summary>   
    public string EvaluatorUser(Match match)
    {
        CultureInfo info = CultureInfo.InvariantCulture;
        String user = Regex.Replace(match.Value, "@", "");
        return string.Format(info, link2, "http://twitter.com/", user, match.Value);
    }
    /// <summary>
    /// Evaluates the replacement for each #Hash link match.
    /// </summary>   
    public string EvaluatorHash(Match match)
    {
        CultureInfo info = CultureInfo.InvariantCulture;
        String linktag = Regex.Replace(match.Value, "#", "%23");
        return string.Format(info, link3, "http://search.twitter.com/search?q=", linktag, match.Value);
    }

And that should do it!