Useful HTML tags

Just a quick note about some useful HTML tags that have been around for a long time, but I've found particularly useful recently:

<del cite="_url_" datetime="_YYYY-MM-DDThh:mm:ssTZD_>

Mark text that has been deleted, optionally citing a URL for more details and a date and time of change. Useful for marking alterations to posts.

<del>Example deleted text</del>

< ins cite="_url_" datetime="_date of change_ >

Mark text that has been inserted, optionally citing a URL for more details and a date and time of change. Useful for marking alterations to posts.

Example inserted text

Definition list - example is this list of tags