i'm actually pretty happy that Google has released their redirector. According to Simon you simply prepend "http://google.com/url?sa=D&q=" to the URL and Google ignores it. i've already taken the liberty of auto adding it to my blog, rendering comments now most unspam worthy.
As an added bonus, i now have another filter for my email traps. Basically, any message that contains links to http://google.com, since spammers will try to mangle the rest of the URL, pretty much like they do with the yahoo "http://rd.yahoo.com/" redirector.
i'm also a little curious about something in the FAQ about the redirector.
2. PageRank-flow fairness. Since blogger.com is linked from google.com, any sites we link to could pass on a fairly high PageRank value. (PageRank is one of the factors that determines what results show up in what order for searches.) In order to remove any possibility of unequal ranking of Blogger-powered blogs in the Google main search index, we send links through a URL from which Google knows to ignore PageRank. This way, Blogger blogs earn PageRank only on the basis of their content and other people linking to them, not because they're powered by a tool owned by Google.
Reading between the lines there seems to indicate that any site linked to directly by a property owned by Google automatically gets a bonus page rank hit. i can only guess that sites picked by Froogle, Adsense and other Google owned properties get that page rank bonus, and in fact, paying to use these services would effectively increase your page rank and traffic.
Hmm.. Paying for placement. Ah well, i'm sure it's quite innovative.
We're supposed to be trying to put an end to them, not trumpeting happily the arrival of another...
It will extract (and optionally lookup ) urls from the path and query portion of a url and then do a surbl lookup. It works within spamassassin.
I'm actually not opposed to the universal google bitbucket approach, partly because it provides a minimal work solution that identifies to any search engine "Hey, don't bother following this", and it's available with minimal effort to any page designer.
Unfortunately, URL mangling isn't consistant across browsers, and since it's yet another redirector, it's an open resorce for spammers to (ab)use, but at least it's a first step.