[suresk]

What makes you think this won't happen with Google?

They have a very valuable patent portfolio, and there is a very high likelihood that Google will at some point experience problems similar to Yahoo, Microsoft, Kodak, etc.

Once that happens, shareholders will be clamoring for that asset to be put to use - if management hasn't already done so to prop earnings up.

And that's why it's so pervasive - the only practical defense to patent lawsuits is building up your own portfolio of patents for defensive purposes. But, since it is highly likely that your company will face situations that require you to utilize that portfolio in an offensive way, your previously defensive patents will require other companies to acquire their own 'defensive' patents. Ad infinitum.

[fpgeek]

Google sometimes attaches patent licenses for non-aggressors for code they've open-sourced (see: WebM). That ties the hands of a future management: the relevant patents are only useful defensively. Anyone not suing Google (or a downstream user of Google's code) for patent infringement related to that code can take advantage of the freely available patent license.

Of course, they're not doing that for everything (e.g. PageRank patents), but to the extent that they do this for the patents they intend to use defensively, they might avoid this problem.