Like so many other media, digital writing started out by copying its predecessors. Academics wrote academic papers and put them on their homepage. Companies wrote serious company things, copying their mission statements and brochures, and posted them online.
But it is in the nature of hypertext to bleed together. That’s its signature feature. Not just links but also aggregation: collections of text collected, mixed, and represented online. And once the various texts begin to bleed together, styles, tones, and voices that are separated by context in print, butt up against each other in digital. The writing of multiple authors appear together. Casual intrudes upon the formal. Conversational text is interspersed with the analytical.
This is both inevitable and proper. Don’t judge hypertext by the standards of print writing. Judge it by its effects on the readers.