The threshold for inclusion of facts in Wikipedia is whether material is attributable to a reliable published source. It does not record personal opinions, experiences, or arguments of the contributors. It also has a project called fact and reference check which verify facts in Wikipedia by multiple independent sources to make it the most authoritative source of information in the world.
I am just giving you an example of what actions are behind one Wikipedia article. Tarif Ezaz, an Wikipedia contributor has just completed his Higher Secondary School Certificate (HSC). Tarif has tirelessly worked over a year to collect information on an article on the Bangla Language Movement to make it a featured article. In his own words:
(I) saw the news "(Bangladesh) Government stopped the program of sending information about Language Movement to all UN nations". I was frustrated to see that news...an idea struck my mind. Yes, we could make it into a Featured Article (of Wikipedia), so that every people who speaks in their own language can get inspired from this.The article has recently been added to the featured articles section.
I made my first edit on August 2, 2006 and had the pleasure to see my own writing added in the article.
I included a lot of information on the article by December 2006, but our main concern was pictures and references. My English was not too good either...I again started writing and on February 2007 we covered most of the historical facts of the article. Ragib bhai asked Rama's Arrow (Nirav Maurya) to improve the article more. I again had the pleasure of sitting back and waiting for things to happen.
On June 16 Language Movement went for FA. I sent what I call SOS to every Wikipedian I know, hoping for help. One of them, of course, replied with enormous interest. Dwaipayan Chokroborti helped to overcome every obstacles over last month. Dwaipayan da stood against all those opposes, copy edited and involved me to gather details about references.
Featured Articles (FA) are a collection of the best articles of English Wikipedia. Right now, there are only 1491 feature darticles which is less than 0.08% of 1.6 million English articles. To become a featured article, a page has to go through very detailed scrutiny by many people, and has to be complete, well-referenced, and neutral.
The interesting thing is that Tarif does not own a computer. He did it all from cyber cafe and using internet via his brother's mobile phone. If one wills he/she can make almost anything possible.
(Via Ragib Hasan)