<INS>, <DEL>

<DEL> indicates that the text has been deleted from the current revision of the document. <INS> indicates that the text has been inserted into the document since the last revision. Both of these tags are currently only supported by MSIE.

this code	produces this
Tell <DEL>Chris</DEL> <INS>Veron</INS> to update the Houston account.	Tell Chris Veron to update the Houston account.

The problem with <DEL> and <INS> is that they don't degrade properly. Browsers that don't know these tags will display the contents of both of them as normal, giving an incorrect representation of the intended meaning. Don't use these tags unless you are sure your audience's browsers support them.