Colin Charles writes about a woman who is selling advertising space on herself . Like Colin I haven’t bought a t-shirt in about 9 years (apart from some Cafepress ones I designed myself). So it seems that the price for getting some significant advertising at a computer conference is to buy a few hundred t-shirts (they cost $7 each when buying one at a time from Cafepress, I assume that the price gets lower than $3 each when buying truck-loads). I have been given boxer-shorts and socks with company logos on them (which I never wore), I think that very few people will show their underwear to enough people to make boxer-shorts a useful advertising mechanism, socks would probably work well in Japan though.
It seems to me that many people regard accepting free t-shirts as being an exception to all the usual conventions regarding advertising. Accepting gifts from companies that you do business with is generally regarded as a bad idea, except of course when t-shirts and other apparel are given out then it’s OK. Being paid to wear a placard advertising a product is regarded as degrading by many people, but accepting a free t-shirt (effectively being paid $7 for wearing advertising) is regarded as OK by almost everyone.
I don’t mind being a walking advert for a company such as Google. I use many Google products a lot and I can be described as a satisfied customer. There are some companies that have given me shirts which I only wear in winter under a jumper. The Oracle Unbreakable Linux  shirt is one that I wear in winter.
Now I would not consider accepting an offer to have advertising on my butt (although I’m pretty sure that it doesn’t get enough attention that anyone would make such an offer). I would however be happy to talk with someone who wants to pay me to wear a t-shirt with advertising when giving a lecture at a conference. I am not aware of any conference which has any real dress requirement for speakers (apart from the basic idea of not offending the audience). The standard practice is that if your employer pays you to give a lecture as part of their marketing operation then they give you a shirt to wear (polo more often than t-shirt). I am currently working on some things which could end up as papers for presentation at Linux conferences. If someone wanted to sponsor my work on one of those free software related projects and then get the recognition of having me wear their shirt while giving a lecture and have me listed as being sponsored by that company in the conference proceedings then that seems like a reasonable deal for everyone.
One thing that you need to keep in mind when accepting or soliciting for advertising is the effect it has on your reputation. Being known as someone who wants advertising on their butt probably wouldn’t be fun for very long.
On the Internet advertising seems to be almost everywhere. It seems that more than half the content on the net (by the number of pages or by the number of hits) either has an option to donate (as Wikipedia does and some blogs are starting to do), has Google advertising (or a similar type of adverts from another company), is a sales site (IE you can buy online), or is a marketing site (IE provides background information and PR to make you want to buy at some other time). Note that my definition of advertising is quite broad, for example the NSA web site  has a lot of content that I regard as advertising/marketing – with the apparent aim of encouraging skilled people to apply for jobs. Not that I’m complaining, I’ve visited the National Cryptologic Museum  several times and learned many interesting things!
I think that Internet advertising that doesn’t intrude on the content (IE no pop-ups, page diversions, or overly large adverts) is fine. If the advertising money either entirely pays people to produce useful content or simply encourages them to do so (as in the case of all the blogs which earn $10 a month) then I’m happy with that. I have previously written about some of my experience advertising on my blog  and how I encourage others to do the same.
I don’t think that space on a t-shirt is any more or less appropriate for advertising than space on a web site hosting someone’s blog.
Finally there is one thing I disagree with in Colin’s post, that is the use of the word “whore“. It’s not uncommon to hear the term “whoring” used as a slang term for doing unreasonable or unworthy things to make money (where “unreasonable” and “unworthy” often merely means doing something that the speaker wouldn’t be prepared to do). But using the term when talking about a woman is quite likely to cause offense and is quite unlikely to do any good. The Wikipedia page about prostitution  has some interesting background information.
-  http://www.bytebot.net/blog/archives/2008/06/13/on-whoring-oneself
-  http://etbe.coker.com.au/2008/02/18/oracle-unbreakable-linux/
-  http://www.nsa.gov/
-  http://www.nsa.gov/museum/index.cfm
-  http://etbe.coker.com.au/2008/04/14/friends-and-adverts/
-  http://en.wikipedia.org/wiki/Prostitution