It is difficult to adjust the content of traditional slide presentations to the knowledge level, interest and role of individuals. This might force presenters to include content that is irrelevant for part of the audience, which negatively affects the knowledge transfer of the presentation. In this work, we present a prototype that is able to eliminate non-pertinent information from slides by presenting annotations for individual attendees on optical head-mounted displays. We first create guidelines for creating optimal annotations by evaluating several types of annotations alongside different types of slides. Then we evaluate the knowledge acquisition of presentation attendees using the prototype versus traditional presentations. Our results show that annotations with a limited amount of information, such as text up to 5 words, can significantly increase the amount of knowledge gained from attending a group presentation. Additionally, presentations where part of the information is moved to annotations are judged more positively on attributes such as clarity and enjoyment.