Bookmarking Posts in a Thread

I was wondering if there was any way to "book mark" a post in a thread. Allowing me to essentially save the last place I read in a thread.

While it's nice that when I open up a thread, it goes directly to the first post I haven't read, but sometimes I may jump around, or open up a thread by accident. Or sometimes I click on the thread just to check out the first post to see if I want to participate, or read the last page first.

Some of these threads can go on for months, and be 30 pages long...it can be difficult to remember the last post I read.

Thanks!