DISCLAIMER 1: some of my best friends are black work in PR. really. me too.
DISCLAIMER 2: i started out as an engineer, then an entrepreneur, then an internet marketer. i probably still suck at all of them, but since 2001 i've done my fair share of tech PR -- both in-house at PayPal and at Simply Hired, working with PR firms at both and other places, and as a marketing / PR consultant to startups i now invest, advise, or consult with.
DISCLAIMER 3: i was lucky enough to hire a really terrific person who did some amazing PR work with me at Simply Hired, who has since gone on to do more amazing stuff at LinkedIn... i hope they realize how lucky they are ;)
now on to the show -- so this is not-quite-a-rebuttal-but-almost to Guy Kawasaki's "Top 10 Reasons Why PR doesn't Work", which seems to paint the perspective of a PR firm primarily pointing the finger of blame or misunderstanding at their client. while i don't disagree many companies & entrepreneurs have highly optimistic or unrealistic expectations of PR; i'd suggest many PR firms are often equally at fault, and don't have a good handle on understanding technology, geeks, or online marketing & social media.
so in an attempt to bring a bit more balance, i present the Top five 6 Reasons why PR doesn't Work, from the geek / tech entrepreneur perspective:
1) The PR firm doesn't understand the product or technology.
especially with tech startups, it's easy for the PR firm to not grasp the basics of the product or service, and subsequently they don't get the best angle on how to present the company's product. or they sound fuzzy or not confident, which can often lead to...
2) The PR firm is seen as a spinner, blocker, or gatekeeper to access the CEO/CTO/braintrust.
while there are a few PR firms which are great about lining up reporters / bloggers / analysts and connecting them with company execs at just the right time, more often than not most media folks would rather bypass the PR firm and talk to someone knowledgeable at the company. this can also occasionally be the case for in-house PR at large companies, whose top execs' time is quite valuable and which they are trying to protect & reserve for bigger media fish... which altho reasonable, still doesn't always build a great reputation with the people writing the articles, especially to the "smaller media fish" or those who might seem to be, as in when...

3) the PR firm hasn't been properly trained on how to communicate with bloggers or social media.
again, there are a few great PR firms (but mostly just individuals) who get blogs & social networks, but most don't. most don't blog themselves, they don't comment on other blogs (very valuable, even if you don't blog yourself), and many aren't really even casual users of many popular social media tools & services. this is a HUGE issue... sort of like doctors who smoke, or heart surgeons who aren't aware of the benefits of exercise & a low-fat diet.
PHYSICIAN HEAL THY SELF! practitioners should know their trade. PR firms should understand blogs, blogging, and bloggers (& flickr, & twitter, etc). most don't. they frequently disrespect & de-prioritize respected & prominent bloggers far below traditional print media, when actually if you look at the resulting impact, the online stuff converts far better, which brings me to...
4) the PR firm prefers doing a few big traditional media over lots of smaller online media & online channels.
i don't fault them here, because it's what they know. and we all like to do what we know, more than what we don't know. still, while there's no doubt circulation for the NYT, WSJ, & WaPO are far bigger than TechCrunch, GigaOm, and ReadWriteWeb; most PR firms miss one critical observation -- for companies whose primary business is online: POUND FOR POUND, WORD FOR WORD, READER FOR READER, CLICK FOR CLICK, ONLINE PR IS SIMPLY MORE VALUABLE THAN OFFLINE PR, perhaps by as much as a factor of 10, possibly even 50 or more. i've seen it. i've seen a 3-paragraph TechCrunch article outperform a 2-page in-depth BusinessWeek print article. i've seen a link in a GigaOm article outperform a bigger mention in the SF Chronicle. i've seen a VentureBeat post on a funding announcement outperform a piece in NY financial media or the SJ Merc.
Why is this the case? Well, it's simple.
Because online converts to online better than offline converts to online.
Try this basic thought experiment: if you're an online service, what are the chances someone reads a blog or website article, and clicks thru on a link? maybe 1-5%, perhaps higher if you're lucky. not great, but not bad... and MEASURABLE. now, what are the chances of someone reading a newspaper or magazine and clicking thru? PROBABLY ZERO. ok, so maybe it's not zero, but they have to leave their current medium (paper), go to a computer, type in the URL (which they might misspell or misremember), and then MAYBE you see a customer. any measurability there? only if you baseline it against normal website traffic. now obviously you want broad demographics & reach, but there is a HUGE benefit to online PR over offline PR simply because the likely conversion to your website is 1-2 orders greater magnitude... at least, that's the case if you're primarily online, which brings me to my final point:
5) the PR firm doesn't understand SEO, SEM, widgets, blogs, tags, social networks, pictures, video, or other online & viral methods, aka "all that Web 2.0 stuff".
hell, you're lucky if most PR folks actually understand how to write a clear & simple email, with a catchy subject line. but there's hardly any chance most PR folks have experience with most of the new online marketing & communication channels noted above, or how to take advantage of them to reach new audience quickly, inexpensively, & effectively. why not? because they're new, and it takes time & effort to study, learn, and become adept at all of the techniques. i sure as hell ain't no expert, and i've been fooling around with it for about 5 years. i'm JUST really starting to figure out what the hell RSS is, and i've been banging my head on that shit since 2003. sigh.
ok, so i'll stop at 5... i could go on, but hopefully the perspective is balanced with guy's top 10. i agree there are issues on both sides of the table, but there's certainly more that most PR firms can do to keep up with the times & the technology. and it's not that i think they are being bad or evil or incompetent here, it's just that the playing field has CHANGED a good bit over the past 3-5 years, and to keep up you have to keep learning & practicing. fact is, most people don't.
however, on the off chance you DO find a good PR firm or individual who gets the stuff above, by all means HIRE THEM. (and if you can, hire an individual in-house ;) there are certainly a few smart PR folks out there... and if they're monitoring TechMeme or their RSS feeds & readers, maybe i'll even see a few chime in here on the comments sometime in the next 24 hours.
speaking of which, there's another one...
6) Most PR folks have no clue what the hell TechMeme is.
anyway, i digress.
UPDATE: Glenn Kelman, founder/CEO at Redfin, posts his own PR top 10 list on Guy's blog.
UPDATE2: additional takes from Brian Solis, Jeremiah Owyang, & a few others.