1script - 2:43 pm on Sep 15, 2011 (gmt 0)
It may be typical but it's not always true. I find it that on forums specifically, the discussion may actually get to the most interesting parts only on page 2 or even further inside, and even without tags that essentially kill off all pages except for the first one, the consequent pages have trouble ranking. I guess, mostly because most internal links are pointing to page 1.
Send users to the most relevant page/URL—typically the first page of the series.
In other words, at least on forums, page 1 may not be the best page you want ranking even on keywords in the title of the discussion so using rel="next" and rel="prev" will just further exacerbate the issue.