Renard Sexton asks if it's for real:
If the bounce simply manifests in a massive burst of support in seats that the Lib Dems already hold, along with a few nearby marginals, the end result could be a pickup of a modest 10 to 20 seats. Similarly, if it comes from alienated opposition voters in safe Labour or Tory seats (tactical/protest voters who would not vote Lib Dem over their own party), again the Lib Dem share of MPs will not budge very much.
All told, Nick Clegg and his cadre will have to play very calculated offense with the rise in support they have gotten. If they can start to turn more races into three-way affairs, and pull disaffected voters from both the Conservatives and Labour, this could get quite interesting.