Of the 20 patent lawsuits filed against Google since late 2007, all but two have been filed by plaintiffs who don’t make or sell any real product or service — in other words, by non-practicing entities or “patent trolls.”

Google goes on by clarifying that in lots of cases, the patents are "invented" by the patent lawyers themselves:

We've also noticed a more disturbing trend: in many of these cases, the patents being asserted against us are owned by — and in a surprising number of cases, are even “invented” by — patent lawyers themselves.

The American Congress is proposing a legislation in the US that would reduce the amount of damages, but the reader will note that it won't prevent Google being sued by patent trolls, so chances to get rid of software patent litigation is not ready to happen:

All too often, Google and other companies face mounting legal costs to defend against questionable patent claims from speculators gaming the system to reap windfall profits. And those lawsuits make it more difficult and costly to introduce the next revolutionary product.

It is to be expected that the companies operating in the US will still continue to be sued in the next years if a more serious reform about substantive patent law is not made. It seems that Congress does not want to touch the Bilski case, probably because the large companies defining the law in Washington wants the advantages of software patents without the disadvantages. This is unfortunately impossible.