This is one of the common questions raised by many visitors to this blog.

The Answer is YES if you are using the Wordpress.Org i,e local install. If you have your blog hosted on wordpress.com there are challenges.

I have personally seen some hosting companies having issues with text widgets.

You cannot copy and paste images into text widgets. Always FTP your images first and then refer to the image inside the text widget.

You can add your optin code to the text widget. Recommended method for putting the optin code is to put it on the sidebar.php without using a text widget. Widgets slow down the response time of your site. Click here to see a video explanation.

Not longtime ago, we had to tweak the wordpress install to artificially increase the number of widgets(Wordpress used to restrict the number of widgets used on a blog to a sizable number, probably for performance reasons). With more and more themes and plugins integrating directly into the code, this problem has become an issue of the past.

Moving on …You can use Iframes in text widgets. You can pretty much do anything with a text widget as text widgets can accept text an html code.