using an address like:
is referencing and anchor. someone using "http://mysite.com/index.php#tabtwo" has "<a name="tabtwo"></a>" in their code where the div or text for tabtwo is located. try putting <a name="tabtwo"></a> where you have "tabtwo" and then place the #tabtwo in your address.
I use this on my companies site so a user can jump to a specific news store based on id number.
i have a link:
<a href="/news/index.html#135">Title of news story</a>
on the news page i have different stories with <a name="(number)"></a>. When the user selects the link it goes directly to the news story number selected even though the link was on a different page.