Go to this page and click on any reply... http://digg.com/2008_us_elections/Palin_Has_National_Security_Experience_AK_is_close_to_Russia
When I tried to post a reply the little hand with a finger appeared but action did not happen.
I can't even load this page right now in my debug build because of bug 20577, but if I load it in the latest nightly (same revision, r36008), I'm able to add a reply just fine.
I cannot reproduce the reported issue in WebKit r39474. Per comment #1 and my experience I close this bug as worksforme.