Does anyone have experience of pinging articles? Would you say it helps them to get indexed quickly - or does Google penalise you for pinging them once (or twice if not indexed to start with)?

I'm currently looking for a way of getting completely rewritten articles in pr3+ directories indexed. I seem to have a few too many sitting there accepted but not indexed and don't want to use the same sb sites to bookmark them all as this would rather say to Google "same author wrote all of these"!

Build links to them with social media sites, blog comments etc. That way they'll stay indexed.