User participation often more or less follows a 90–9–1 rule:

• 90% of users are lurkers (i.e., read or observe, but don't contribute).
• 9% of users contribute from time to time, but other priorities dominate their time.
• 1% of users participate a lot and account for most contributions: it can seem as if they don't have lives because they often post just minutes after whatever event they're commenting on occurs.

Backtracking ist eine der wichtigsten Navigationstechniken. Es bringt den Benutzer zum vorherigen Knoten zurück und machent somit den letzten Hypertextsprung rückgängig.

The system should be efficient to use, so that once the user has learned the system, a high level of productivity is possible.

The system should have a low error rate, so that users make few errors during the use of the sysem, and so that if they do make errors they can easily recover from them. Further, catastrophic errors must not occur.

The system should be easy to remember, so that the casual user is able to return to the system after some period of not having used it, without having to learn everything all over again.

The system should be pleasant to use, so that users are subjectively satisfied when using it; they like it.

Usability has multiple components and is traditionally associated with [the] ... five usability attributes: learnability, efficiency, memorability, errors, satisfaction.