Moneyterms is safe from the malicious insertion of falsehoods. A discussion, on Wikipedia itself, of once such hoax, includes the assertion that (according to Wikipedia policy) it does not matter if something is true or false, as long as there are sources to cite! Given that the cited sources appear to have got their facts from Wikipedia, this means that anything that is repeated often enough may be presented as a fact on Wikipedia.
There was also this interesting test [link removed October 2009 as it no longer works] of Wikipedia contributors' ability to correct malicious insertions.
I do not want to be too negative. I find Wikipedia to be a useful resource on certain subjects. My approach is to use it when the topic in question meets two criteria. Firstly, no one should have a strong motive for making biased edits. Secondly, it should be a subject that interests the type of people who are likely to be Wikipedia editors: I have, for example, recently used Wikipedia to find out about column oriented databases, and to get a Doctor Who plot synopsis.
For those who would enjoy a more sustained attack on Wikipedia, I suggests Wikipedia Watch, Wikipedia Review and (with the caveat that you may find its sense of humour offensive) Encyclopaedia Dramatica.
This is why Moneyterms relies, as far as possible, personal experience and primary sources: the site has many links to academic research. Where neither is possible I try to find multiple authoritative secondary sources. I prefer to not write an entry, than to compromise quality, and I have deleted pages that I later decided did not meet my standards.
The result is that, in the three years since the site launched, I have found only one serious conceptual or factual error. The site is much better checked and proof read now than it was when a reader emailed me to point out that error. With over ten people a day reading the average page on the site, and with my own continuing improvements and revisions, mistakes are now hard to find.
As I said earlier, I think there is a more general pattern in the quality of websites. The most reliable, and highest quality websites are written by one person, or a small number of people, who have meaningful expertise on, and are themselves deeply interested in, the subjects they write about, and who stick to what they know. This is why, for example, I now rely on blogs written by economists for economic new and analysis, rather than on newspapers written by journalists.