BlogPage.cs

public partial class BlogPage
{
    private readonly IWebDriver driver;
    private readonly string url = @"http://automatetheplanet.com/blog";

    public BlogPage(IWebDriver browser)
    {
        this.driver = browser;
        PageFactory.InitElements(browser, this);
    }

    public void WaitForSubscribeWidget()
    {
        new WebDriverWait(driver, TimeSpan.FromSeconds(30)).Until(ExpectedConditions.ElementExists((By.ClassName("subscribe"))));
    }
}