What's the nature of useless information?
Information seems useless to people receiving it when it's lacking a significant context. There's no reason to be getting the information right then in the way it's being delivered. It serves no purpose for the supposed beneficiary.
Why is it so common to provide useless information, regardless of the people receiving it?
It's usually very useful to provide information for the provider. Publishers of print books, magazines, mailers and newspapers all get paid for dishing out information. Their deal is sealed by providing the information, not by how it's applied or put to use. Educators, teachers, trainers and professional speakers all receive remuneration for being informative regardless of what people do with the information in their own worlds. Institutions that confer diplomas, transcripts, certificates of completion or other credentials -- assume the value of the information is evident in qualifying for the "piece of paper". They create a self-contained world that makes getting the credential the end result, rather than the means to an end.
How does digital text make information more valuable to the receiving end?
The digitized archive of information can be searched for potentially useful links. The searcher's context of use provides the premise, key words and criteria for evaluating search results. When new content is getting published online, the end user can subscribe to continual searches of RSS feeds for relevant information. When a potentially useful wiki is getting updated, the changes in the wiki (or specific pages) can show up in a blog reader or be sent as emails. Digital text has addresses that can be bookmarked and tagged with one's own labels. Those tags used by others can also be searched.
What's different about finding useful information for oneself?
It's like being allowed to look around in a library on one's own instead of being herded to the stacks en masse to get a book read to you by an expert at a scheduled time. The information gets received only when it's needed to answer a specific question, solve a problem or make some other unique difference to the searcher. The power, control and curiosity are in the hands of the receiver, not the provider. The beneficiaries actually benefit from the information because it comes to them on their own terms. They gain confidence in their questions and particular interests. They realize how easily they retain information they found useful according to their own contexts. They get better finding what serves their quest to understand something better.