What's the best strategy for linking to tier 1 2.0 properties?

Many of the services that initially build 2.0s will send about 1k or so links to them. Is it beneficial/important to continue to push links to them?

How much link building do I need to do per month, and what kind of links? Automation, is it OK?

The goal is to increase the 2.0's Page Rank, correct?

Please don't remind me the board has a search feature. I'm having trouble finding answer.

Thank you.