Is there any practical difference between an extension method on <T> or on Object?
<p>Is there any practical difference between these two extension methods?</p>

<pre><code>class Extensions
{
    public static void Foo&lt;T&gt;(this T obj) where T : class { ... }
    public static void Foo(this object obj) { ... }
}
</code></pre>

<p>I was poking around in <a href="http://extensionoverflow.codeplex.com/" rel="nofollow">Extension Overflow</a> and I came across the first form, which I haven't used before. Curious what the difference is.</p>
