Without technical tools a lecturer can rely only on his capacity to clearly present the matter and establish a good relationship with the students.   It is highly likely that in such a lecture dialogs or even debates with the students will be more prominent.

A blackboard enables a lecturer to attract the attention of his/her students to the most important sections of the subject matter. Most people are audio-visual types and find it easier to memorize the data which they have heard and seen at the same time.

Chalk and blackboard make possible good quality lectures with minimal technology use. Technical development led many teachers to present the information they used to write on the blackboard with an overhead projector or computer presentations.

Use of technology does not necessarily guarantee progress. Chalk and blackboard remain a popular technique, especially with mathematicians. The justification for this fact is that much better omprehension can be achieved through e.g. gradual development of a mathematic formula on a blackboard, than if the same formula is presented on screen. Another factor is the speed at which a lecturer writes on the blackboard, which is adjusted to the speed the students write/understand the matter.