There are benefits and drawbacks to either answer to the question "Should Wikipedia be funded using advertising?".
If yes, the Wikimedia Foundation would have a huge surge in revenue. Donations could play second fiddle to the advertising money that would allow the Foundation enough money to pursue whatever enterprise it wanted, such as launching regular print (or otherwise physical, I imagine Blu-Ray or DVD being ideal) editions of Wikipedia, hosting those Wikipedia Academy events worldwide, or hiring more programmers to improve the MediaWiki software (debugging
FlaggedRevs would be high priority). There would be enough money that could buy servers just for the capacity to enable features currently disabled on Wikipedia because of the current lack thereof, like integrated spellcheck, suggestions for search, and dynamic hit counters. With what Wikipedia has achieved on a tiny budget of a few million dollars (consider this relative to Google's billions upon billions), it could achieve so much more if we were to ratchet up the budget by a few orders of magnitude.
On the other hand, advertising can be seen as fundamentally degrading to the content - regardless of whether it actually influences the content, it will influence how the content is seen - content presented with ads beside it is somehow different from content that is simply presented. Visual, intuitive measures of trustworthiness decline when content is accompanied by ads, because there is a sense that someone is doing this for a particular purpose, that there is some sort of corporate motive behind what is presented. Wikipedians who cannot abide advertising beside their work would leave and either fork the project or abandon it; the sense that one's unpaid work earns money for another is frustrating to someone even if that other is merely a beneficent organization seeking to perpetuate that work. The mere suggestion of advertising caused one fork already - should advertising be raised again, the split in the community might be devastating. There is a reason that Wikipedia calls its members "Wikipedians" - a
demonym - rather than "Wikipedists" or "members": the community is essential to the maintenance of the resource as a whole, and as one of them (an admin), I certainly know this on a first-hand basis.
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If no, the Foundation does maintain some risk of financial trouble - it is expensive merely to maintain the servers and pay for bandwidth, and the database is huge. The risk is of the free content winking out into the dark, to be perpetuated merely by mirrors and forks - many of which (illegally) try to claim that the content is their own and copyrighted (rather than the GFDL under which Wikipedia content is licensed). The key thing is that what's been created is available for anyone - if you have the bandwidth and the time, you can download the database and start your own fork.
It's not completely a doom & gloom scenario yet - the planned $4.6 million budget drawn up included plans for
growth, not merely maintenance. By keeping to the baseline, the budget could be successfully slashed.
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Overall, it's a bit of drama - while the publicity will certainly be good in that not many people seem to realize that Wikipedia runs on a shoestring budget - the site's relatively professional look and feel, not to mention the lack of ads, would seem to suggest that Wikipedia isn't worried about money, that someone runs the site and people don't have to care.
People do have to care, because ultimately Wikimedia needs a pile of those funny green (or multi-colour, here in Canada) things from your wallet to keep running, to serve up billions of pageviews, to keep a lawyer and an accountant on staff, and those other necessary things.
Personally, if advertising came to Wikipedia, I'd not worry - I know intuitively that it's not about the money, it's about keeping the goodwill going out even if it's hard to get it to come in. I'd certainly be disappointed though: in an ideal situation, Wikipedia would have funding that would let it do the great things for which it has the potential, without having to sell its space and credibility for the money it needs to run. That we can continue our ideals for the moment is good; but we should never forget the baseline goal that's been set out.
