WebProNews

More stats regarding Facebook's astonishing growth rate were released today.  Hitwise puts the social network's market share of U.S. Internet visits up on a month-over-month basis, way up on a year-over-year basis, and it made significant gains in the "time spent" category, too.

Let's first look at the market share data.  Hitwise created a custom category of social networking sites, and within it, Facebook's market share was 58.59 percent in September of this year.  That puts it up by a fair amount over its standing of 55.15 percent in August.

Then, moving further back in time, the 19.94 percent share it controlled in September of 2008 is just tiny by comparison.  Indeed, Facebook pulled off a 194 percent year-over-year increase.

As for the number of minutes Facebook users are spending on the site, Hitwise found that it increased by 23 percent since the same time last year, which is impressive, too.

Meanwhile, Twitter and MySpace weren't nearly so lucky.  Twitter's market share has skyrocketed by 1,170 percent year-over-year, but the time spent figure has decreased by a whopping 56 percent.  And MySpace lost ground in both categories, by 55 percent and 12 percent, respectively.