May I also offer a suggestion (which I’ve just gone ahead and done) for allowing a tag {encoded_url} as I am constructing a message to StumbleUpon visitors to be able to also “like” the post from the welcome graphic.
So my body content looks like:
<a href="https://www.stumbleupon.com/submit?url={encoded_url}"><img src="https://domain.com/wp-content/uploads/StumbleUpon.jpg" alt="Stumble Upon"></a>
To achieve this I added “<img>” to the approved tags and changed the prepare_post_data method in rd.class.php inserting:
$encoded_url = urlencode( get_permalink($post->ID) );
after the url variable and inserting:
'encoded_url' => $encoded_url,
Into the $data array.
This may be against what you were intending but it fits our immediate needs… Just wanted to give you a heads up in case you like the idea and would consider it in a future update.