<b><i>REVISED:</i></b>
This is a popular form of Internet shorthand used on the DIS Boards. People tend to use this shorthand to abbreviate their references to people in their family. But there's some difference of opinion as to the translation of these abbreviations. Some people believe the "<b>D</b>" stands for "<b><u>D</u></b>ear". Others believe it stands for "<b><u>D</u></b>isney". I prefer to believe it stands for "<b><u>D</u></b>arling". So a translation table might look like this:<blockquote><table border=1 bgcolor=white><tr><td><table border=0 cellpadding=10><tr valign=center><td align=right><font size=2><b>DD<br>DF<br>DH<br>DM<br>DS<br>DW<br><br>DBIL<br>DFIL<br>DMIL<br>DSIL<br><br>DBF<br>DGF<br>DSO</b></td><td>=</td><td align=center><font size=2>[ <i>your choice of</i> ]<br><br><b><u>D</u></b>ear / <b><u>D</u></b>arling / <b><u>D</u></b>isney</td><td>+</td><td align=left><font size=2><b><u>D</u></b>aughter<br><b><u>F</u></b>ather<br><b><u>H</u></b>usband<br><b><u>M</u></b>other<br><b><u>S</u></b>on<br><b><u>W</u></b>ife<br><br><b><u>B</u></b>rother-<b><u>i</u></b>n-<b><u>l</u></b>aw<br><b><u>F</u></b>ather-<b><u>i</u></b>n-<b><u>l</u></b>aw<br><b><u>M</u></b>other-<b><u>i</u></b>n-<b><u>l</u></b>aw<br><b><u>S</u></b>ister-<b><u>i</u></b>n-<b><u>l</u></b>aw<br><br><b><u>B</u></b>oy<b><u>f</u></b>riend<br><b><u>G</u></b>irl<b><u>f</u></b>riend<br>"<b><u>S</u></b>ignificant <b><u>O</u></b>ther"</td></td></table></td></tr></table></blockquote>There are other variations possible, but you probably get the idea.
Sons and daughters will sometimes have a number appended to the <b>DS</b> or <b>DD</b>. That number would be a reference to their age. So if I referred to my <b>DS5</b>, I would be talking about my 5-year-old darling son.