Please read the following table in HTML format from a webpage and then answer the question in detail according to the table. Each table cell is defined by a <td> and a </td> tag. Each table row starts with a <tr> and ends with a </tr> tag. 'rowspan=m' and 'colspan=n' represents a cell spaning over 'm' rows and 'n' columns.

Webpage title:
List of Strikeforce champions
Table title:
Welterweight Championship
Table:
<table id='hittask' contenteditable='False'>
<tr> <th colspan=1 rowspan=1 > No. </th><th colspan=1 rowspan=1 > Name </th><th colspan=1 rowspan=1 > Event </th><th colspan=1 rowspan=1 > Date </th><th colspan=1 rowspan=1 > Defenses </th></tr>
<tr> <th colspan=1 rowspan=1 > 1 </th><td class="highlighted"  colspan=1 rowspan=1 > United States Nick Diaz def. Marius Žaromskis </td><td colspan=1 rowspan=1 > Strikeforce: Miami Sunrise, FL, USA </td><td colspan=1 rowspan=1 > January 30, 2010 </td><td colspan=1 rowspan=1 > 1. def. </td></tr>
<tr> <td class="highlighted"  colspan=5 rowspan=1 > The title was vacated on June 9, 2011 when Diaz's contract was absorbed by the UFC. </td></tr>
<tr> <th colspan=1 rowspan=1 > 2 </th><td colspan=1 rowspan=1 > United States Nate Marquardt def. Tyron Woodley </td><td colspan=1 rowspan=1 > Strikeforce: Rockhold vs. Kennedy Portland, OR, USA </td><td colspan=1 rowspan=1 > July 14, 2012 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <th colspan=1 rowspan=1 > 3 </th><td colspan=1 rowspan=1 > Belgium Tarec Saffiedine </td><td colspan=1 rowspan=1 > Strikeforce: Marquardt vs. Saffiedine Oklahoma City, Oklahoma, USA </td><td colspan=1 rowspan=1 > January 12, 2013 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=5 rowspan=1 > The Strikeforce Welterweight title was vacated after the Strikeforce banner was dissolved into the UFC on January 12, 2013. </td></tr>
</table>
Question:
What happened to Nick Diaz's welterweight championship tittle in 2011?
Answer:
Nick Diaz vacated his Strikeforce Welterweight Championship title.