There are a number of ways of increasing your inbound links that have nothing to do with your authority on a subject:
The two primary culprits here seem to be trackback pings and, more importantly, comments. For instance, while the number of visitors I receive to this site has increased only marginally (about 20%) over the last few months, my PageRank has gone from 5 to 6, equal to blogs like En Banc and Crescat Sententia (though a rank below The Volokh Conspiracy). I don't have anywhere near their readership.

On the other hand, I have a loud mouth and a habit of commenting on other blogs. Doing a Google search for blogs that link to mine, I find quite a few hits that are nothing more than comments that I've left on others blogs. From this, it seems that I'm generating my own publicity, and indeed my own Google Juice.

I would think that Google would cut back on the 'authority' of such posts, and so long as most blogs keep a standard format (comments on pop-up or individual entry pages) then that's fine: the vast majority of 'self-generated publicity' can be weeded out by altering the search patterns of Googlebots. But what happens when the pattern becomes non-standard? For instance, over on Crescat I get an inbound link on both Google and Technorati whenever I post a trackback ping to their site. This would seem a bit more difficult to modify in Google's rankings.

When Google does modify things, my PageRank is likely to plummet
The caveat to the above should be that I'm judging PageRank solely on the Google Taskbar, which may not give accurate rankings. But at the moment, it seems to consider me a six, and I get a certain amount of perverse pride from that. Still, as mentioned above I think much of this is artificial, and I expect a plunge soon.

All told, I'm not sure this is a bad thing. As I've noted, many of my inbound links are for subjects on which I'm definitely not speaking. (My classic example is misty rain piercings, which for a while ranked me above not only most porn sites, but even above such more topical sites as SuicideGirls (warning: not work safe).) I'd rather have people coming here because they're interested in my personal experiences at law school or my political views, not in a sure-to-be-disappointed search for porn.

Further, getting rid of the 'Google Juice' one gets from comments would probably cut down on the activities of comment-spammers (those odd, random, and inappropriate comments you sometimes find here before I delete them), because a lot of the value would go out of them. So despite my pride, it might not be a bad thing.

Some of the best methods of 'audience building' may not be entirely above board
A couple of new bloggers have asked me recently, 'How do you build an audience.' My general advice is 'write often, write well, and fill your niche.' But obviously, one of the best ways is to increase your ranking on Google. And based on what seem to be my 'results', the best way of doing that would seem to be:

1: Make extensive use of trackback pings to other, higher-page rank blogs; and
2: Comment frequently on same. (Make sure that you leave your name and a link back to your site.)

On the other hand, I'm really not sure this is the best way to attract readers directly, and not something I'd suggest simply to increase one's readership. Not because it wouldn't work (I think it would), but simply because it would lead to a lot of irrelevant, banal, and uninteresting comments left by people who have little to say, and just want to push themselves up in Google's esteem.

Anyway, these are just guesses at what may or may not happen in the next few months. Anyone who has some more fact-based assertions, feel free to comment.