>Is there a published list of acceptable (and unacceptable) tags to be used in UT messages and signatures -- and how would I get this list?

Perhaps the best place to start would be with a fairly complete list of the HTML tags - and a good source for that is "Instant HTML Programmer's Reference" from Wrox Press, ISBN 1-861001-56-8. Appendix A is entitled The Wrox Ultimate HTML Database Listing, which is an alphabetic list of the HTML element tags, describing what they do, which browsers/versions support them, and their available attributes. Appendix B offers the list of Tags by category of function. Appendix C shows how you display special characters. In D, you'll find the standard color names. It's a good introduction to HTML, and can dramaticly enhance entries here - judicious use of HTML tags can emphasize or delineate pertinent segments of posts, and even insert links to other useful web pages where appropriate (I do this in my signature so others have a simple way to get to some non-VFP sites that I refer to frequently.)