According to www.w3schools.com, “an element with position: absolute is positioned at the specified coordinates relative to its containing block”. Using this command, you can work various sorts of magic that would normally require the paid CSS upgrade: you can put code in a text widget and make something show up at another point on the blog page instead of the sidebar or bottombar.
In its most basic form, the code model is this:
ELEMENT_HERE
</div>
Various additional commands may be needed, depending on the theme and the particular element to be positioned.
Note that the top (or bottom) and the left (or right) px numbers are offset numbers: if, for instance, you increase the top number, the element will move downwards.
Example 1
In my primary blog I’m using Chaotic Soul. I hated the original “Get a free blog” notice in the footer, so I masked it with a strip in a color identical to that of the theme background. Code:
The footer includes a link to the designer’s site as well; hiding that isn’t fair, so I transferred it to a text widget. Before/after snapshots here.
Example 2
Unsleepable has a plain black header, with no built-in option for inserting a custom header image. You can do it with the following code:
<a href="BLOG_URL_HERE"><img src="IMAGE_URL_HERE"></a>
</div>
The dimensions of the image need to be 776 x 100 pixels. The image must include the blog title, since the original one will be masked. In designing the image you must take into account that logged-in wp.com users get the grey admin bar up top, which will hide the upper 28px of the image. For a specimen, check this feast of a blog (fellow forum volunteer Tess).
Example 3
Ocean Mist has navigation tabs in the header, but with no “Home” link. By way of an exercise rather than a recommended solution, here’s a code for a home tab:
<div style="width:702px;">
<table border="0" align="left">
<tr>
<td style="background-color:#526A74;padding:6px;">
<a href="BLOG_URL_HERE"><span style="color:#f3f3f3;"><h4>Home</h4></span></a>
</td>
</tr>
</table>
</div></div>
Result:

This example also serves as an introduction to the problems you get with many themes: in contrast to Unsleepable, in this case the presence or absence of the grey admin bar will affect the placement of the element. The image above displays what logged-in wp.com users will see; for other visitors (or for logged-out wp.com users) the tab will show up lower. In the next post on position absolute, there’ll be a complete report on all themes re this and other shortcomings.


