I've been a faithful WP.org user for years now, but have created a WP.com blog for a different purpose and have a question regarding what CAN be done in terms of plugins on WP.com.
The situation is as follows. Author posts URL example.com/widgets, and I want the URL to be automatically modified to add a query string, turning the URL into example.com/widgets?subid=1
Is there such a plugin? Or if one were written, could it be used on a wp.com blog?
And now, to complicate things, I only want the string to be added if the URL is from a shortlist, and not ANY ol' URL they might post.
[Edit: Forgot to mention, if none of this is possible, I CAN either moderate each author's entry or teach them to add the string, but it'd be fab to be able to cut out the manual process]