1. Google is definitely not "anti-patent," either philosophically or otherwise. At the heart of its business is the PageRank patent, which is assigned to Stanford with exclusive license to Google. Even within the last month, Google got a patent for its "Systems and methods for enticing users to access a web site," i.e., its "Google Doodle" (see http://ipwatchdog.com/2011/03/25/google-patents-the-google-d... for an overview on this). And, of course, the blog post involved here very carefully delineates and distinguishes patents that foster innovation (presumably good) and others that are primarily gained to foment litigation, in particular "low-quality software patents."
2. Of course, Google is involved in a current, major fight involving Oracle's assertion of both copyright and patent Java-related claims against its Android technology. Google is a powerful adversary to take on, and it is blasting away quite skillfully seeking to invalidate the Oracle patents in that suit on Bilski grounds that they constitute "abstract ideas" and not bona fide patentable subject matter (see http://news.ycombinator.com/item?id=1899156 for a summary of relevant issues in that case). But no powerful litigant ever bets solely on how a court might interpret some nebulous body of law such as what constitutes patentable subject matter. As matters now stand, should Google lose on that issue, it has very little in the way of defense against such claims. Perhaps the patents upon which it is bidding will give it a practical way to attack Oracle so as to bolster its defense but, again, I don't know about the immediate portfolio or whether it even relates to the Java-related claims. That said, however, I am certain that the Oracle litigation, at a minimum, has spurred Google to consider this issue very carefully and to determine that it needs these tools very badly so as not to be exposed in the future to patent broadsides to which it has no answer other than to point out how weak the relevant patents are - which may be no answer at all in the real world of patent litigation. Hence, this patent portfolio bid has either an immediate aim in mind (Oracle litigation) or a long-term aim with the same strategic view in mind (cover yourself against flim-flam patent claims that might hinder Google's future ability to innovate).
3. The FTC recently issued a comprehensive report on the need for patent reform, and one of its main points concerned so-called "non-practicing entities" or what it has chosen to call "patent-assertion entites" (PAEs) or what is commonly known as "trolls" (see HN discussion here: http://news.ycombinator.com/item?id=2303980). These are patent holders who do not use their patents to produce things but rather use them solely for licensing and the concomitant litigation that inevitably follows against those who decline the licensing "offer." In reality, the PAE idea is much more complex than merely that of a shakedown racket. All sorts of large tech companies routinely gather up all sorts of patents for which they have no plans to innovate but which are vital to their business strategies, either to be used to attack rivals or to defend against them and whether for good or for bad motives. In making this bid, Google is basically acknowledging that it needs to arm itself in this department. This is neither inherently good or bad and could be used strictly for protecting Google's ability to innovate or it could be abused down the road, all depending on future choices to be made by the company's management. It is certainly a double-edged issue.
Groklaw recently ran a piece answering the question "what's blocking innovation in America" and answered it with "IP laws" - this in turn led to some sparks flying here at HN as some, like me, defended IP in general while saying that it needs to be reformed and (many) others taking the more radical view that IP laws generally are to be castigated (http://news.ycombinator.com/item?id=2210469). In my view, the case for IP laws generally is made by companies such as Google, which uses such laws effectively and powerfully but which, at least to date, has not abused them. In this sense, Google has been an exemplary company on this issue. What the future may bring on this front, of course, remains to be seen.