Does the Panda update effects in normal off-page optimization? Like people used to submit articles and PR in various article and PR directories in a day. Will it be possible now? Is there any restriction on number of submissions per day?
No there is no any type of submission limit after panda update. But you should make spin your article before submit it in different directories.
panda is all about quality and original content, if you submit same article on various article directory then it will not helps you much in order to get ranking and backlink as well.
I was talking to a few SEO experts and they all said to me that off page optimization has no changed, only on page.
The panda is up against duplicate content. And about submitting one article to various article submission sites, I think it is ok as long as you put your signature in your article. This is just my opinion.
After Google Panda, Google is not penalizing article submissions that are unique. What it IS penalizing is the submission of the same article to a number of different directories. Google penalizes duplicate contnent and if you are doing it this way, you are inviting Google to punish you. Bad for business and ranking. Remember to submit unique articles on the web.