The text elements

The <p> element

The commonly used attributes on p are unsurprising:

A few sites use the dynamicanimation attribute on the p element, a FrontPage extension. A few also used the language attribute, though we cannot determine why. If it was an attempt at specifying the lang attribute then one would expect to see a lot of successful attempts, but in fact there weren't enough pages that used that attribute on the p element to even register on the radar, so it seems unlikely that that is the explanation. Maybe attempts to set the script element's attribute of the same name?

The <br> element

The br element is a simple one, yet used on so many pages that it is the 8th most-used element. It is used more than the p element.

There are very few legitimate semantic places to use this element (addresses and poems are the canonical examples), which means that most uses are probably presentational. Its two most commonly used attributes are certainly presentational, and the third is almost certainly used presentationally as well.

The soft attribute doesn't appear to be supported by any modern browsers. We couldn't find any formal documentation for it; presumably it is an obsolete Netscape feature.

The \ "attribute" is almost certainly the result of people writing markup like <br\> when intending to do <br/>. Of course, neither is particularly useful to browsers when the page is sent as text/html (as all these pages were).