I thank Gianluca I recently met at the OnlyWinefestival and Marta (who wrote me using the “requests” section of my blog) who have asked such a question.
Wine experts are absolutely used to run those kind of tastings but for those who are now approching to the wine sector it is not easy to understand all of the technical terms.
VERTICAL TASTING: tasting of the same wine (same producer), different vintages in order to analyze the evolution of the wine year by year.
HORIZONTAL TASTING: same vintage (generally same grape or at least same territory/area), different producers to analyze the different styles.
BLIND TASTING: tasting of wines without knowing the producers. This is the method used at the wine competitions to guarantee an impartial evaluation. Judges, in these cases, are often prodived with a sheet including some basic information (ex. grapes).