Make your Twitter share links open as a small popup window so the user can still see your page in the background.
This jQuery snippet will open your Twitter link in a window the perfect size for the Twitter sharer. It will focus the popup so it comes to the front. If the popup was blocked by a popup blocker it will allow the default event behaviour to run so the window opens as a _blank.
For more options with Twitter sharing go to: http://dev.twitter.com/pages/tweet_button