"They attend to auspices and lots like no one else. Their practice with lots is straightforward. Cutting a branch from a fruit tree, they chop it into slips and, after marking these out with certain signs, cast them completely at random over a white cloth. Then a civic priest, if the consulation is official, or the head of the family, if private, prays to the gods and, gazing up at the heavens, draws three separate slips: these he interprets by the previously inscribed mark. If the lots are opposed, consultation on that matter is over for that day; but if they allow, the confirmation of the auspices is still required." (Rives translation)
"For omens and the casting of lots they have the highest regard. Their procedure in casting lots is always the same. They cut off a branch of a nut-bearing tree and slice it into strips; these they mark with different signs and throw them completely at random onto a white cloth. Then the priest of the state, if the consultation is a public one, or the father of the family if it is private, offers a prayer to the gods, and looking up at the sky picks up three strips, one at a time, and reads their meaning from the signs previously scored on them. If the lots forbid an enterprise, there is no deliberation that day on the matter in question; if they allow it, confirmation by the taking of auspices is required."(Mattingley/Handford translation)
The priest or the rune reader confirms the reading via other means such as the calls and flights of birds and the interpretation of the neighs and snorts of sacred horses. So it is clear from Tacitus that the ancient Teutons relied heavily on these magical and divinatory practices. That however does not make them unique but it does demonstrate that the runes originally had a magical character and origin which was confirmed a millenium later in mediaeval Iceland in the Eddas and Icelandic Sagas.
Of course Tacitus does not use the term runes as this most likely was unknown to him. The term Tactitus uses is notae (signs). Whether these notae resembled the Common Germanic or Elder Futhark runes no one can say but Dr Stephen Edred Flowers in his Runes and Magic points out that the Meldorf brooch (ca. 50 CE, Schleswig) does contain "inscriptions of probable runic character". The brooch thus dates 48 years prior to the publication of Germania.
Another thing that strikes me as interesting about the Germania reference is the fact that the runes could be read and were read not just by priests but by the head of the household. This being the case it would suggest that runic knowledge was far more widespread than is currently appreciated. Also it causes us to question how this fits in with the notion of the more specialised Rune Master.
The method of reading the runes referred to in Germania is in my opinion one of the simplest and yet most effective. There is a danger that by introducing too much complexity into our systems that we move away from the numionous to the human realm; something we must avoid doing.