There used to be a way to see all the posts you have ever made here.

Is it still possible?

Yup.
How can I see someone's old posts?
You can click on the 'Posts #' beneath their forum picture.
Or, if you cannot find that:
http://mingle2.com/forum/show_posts_by_user/XXXXXXX

Where the 'XXXXXXXs' represent the user-number.
If you know the user-name, you can right-click on
it anywhere (profile, forum, mail, etc.) which
renders a drop-down menu, select 'Properties' and
copy the URL (link shown)..the last digits of
which will be their user-number.

Place that number where the 'XXXXXXXs' are above.

To see beyond the 25 pages shown, merely change
the last digits in the address bar to represent
ascending numbers.

This is easiest if you click on a page first, like 25,
at the bottom.

As an example, if I clicked on Page 25 of your posts,
the address bar would read thus:
http://mingle2.com/forum/show_posts_by_user/XXXXXXX?page=25

To see beyond Page 25, you would change the 25 in the
address bar to 259, or 500, or as far back as you can find :-)