The House of Representatives adopted a package of approximately 50 “tax extenders” that will allow a range of tax credits and breaks to continue for this year.  This year, 2014. The package costs approximately $42 billion for this one year extension and it would have to be renewed again by late next year.  The cut in federal revenue is not being paid for as required of child welfare legislation earlier this year when it would have cost less than $4 million over ten years.
The one year tax package is actually narrower than the extension that what was being discussed during the Thanksgiving break.  There had been discussions between House and Senate leaders on a package of tax extenders (the same that are in this new proposal) but those discussions would have made some business breaks permanent and extended some family based credits (for example, the child credit and earned income tax credit) for two years.
Reports are that as negotiations continued the Republicans were no longer willing to include these family-based extenders out of concern that some immigrant families might benefit.  The package would have cost over $400 billion again with no way to offset the costs.  As word of negotiations and the shape of the package became more public the White House reacted with a threat that the President would veto such a proposal.  That put a stop, at least for now, of a bigger permanent tax package, unpaid for.