All magazines are limited by space. But a website can have a virtually limitless amount of text. This allows websites to go into a kind of depth that magazine editors can only dream about. Linking to other resources, internal or external, is infinitely easier on a website. In a magazine article, you can refer readers to a pamphlet or article or even a website but in a website, you can make such references links.
Readers are only a click away from more information.
The printing and distribution costs of magazines are extremely high, which means that unions are sometimes obliged to limit circulation of some publications when ideally every member would receive them, or publish quarterlies when monthlies would be more appropriate. On the net, having more readers doesn't add to cost. In fact, the opposite is the case. The more readers visit a website, the more valuable the site becomes. In part because of the above, the very idea of a website being updated quarterly or monthly sounds strange.