As mentioned in a previous post, I spend more time on LinkedIn these days. Here are some more hints I've picked up from other people recently which are worth sharing.
Connect your Twitter account to your LinkedIn profile. I prefer to post updates from Twitter, but it will work both ways if you want. However, watch what you Tweet once you've done this. The best approach is to use the #in and #li tags to control propagation to LinkedIn. As ever a Google will lead you to useful resources, here's a random one from a search I did.
Hide updates from connections who update too frequently or whose updates are irrelevant. You can do this by clicking on the "Hide" button, but be aware this only appears when you hover your mouse over an update:
Watch the frequency and relevance of your updates, whether via Twitter or directly on LinkedIn. See above, don't let your updates be the ones that get hidden by others in your network, given the number of steps needed to reverse the decision, it's likely that once a connection has decided your updates should be hidden, they'll remain hidden.