Online collaborative encyclopedia Wikipedia has a massive 97% share of internet visits among the top five reference websites, highlighting the amount of work that rivals like have to catch up. announced some new Wikipedia-style community features last week as it attempts to make up some of the ground lost to Wikipedia. According to stats from Hitwise, it currently has just 0.57% of US internet visits to the encyclopedia category.

Other reference sites like MSN Encarta and also trail way behind Wikipedia, but comes bottom in this category:

Hitwise encyclopedia stats

Britannica president Jorge Cauz also complained about Wikipedia’s superior search engine rankings, but it could do a lot more to optimise its site for Google. Wikipedia is well designed for SEO; its link structure, title tags and meta descriptions all work well on Google, as well as the millions of links into the site from other sources. Meanwhile, much of Britannica’s content is locked away for subscribers only, making it harder for Google to index, and less attractive to link to.

As we pointed out last week, usability is also a big issue. is not especially usable, with too much Flash, intrusive ads and poor site search among the problems.

Compare the entries for ‘World War Two’ on the two sites. Wikipedia comes third for the term on Google, while Britannica is nowhere. Perhaps Britannica’s entry is more authoritative than Wikipedia’s, but I can’t find out easily because it is locked behind a premium content wall, and requires users to sign up for a free trial, which involves entering card details, something few users will be happy about:

WW2 entry

The other three encyclopedias on the list also lag well behind Wikipedia for usability, even though others like rank better than Britannica, while Google Knol is a big disappointment so far. Clearly, all these sites have a lot of work to do to close the gap.