There is a considerable amount of talk as to what should and should not be considered for looking at when talking segment lengths. SOme use the 5cm, some 7c, some 10cm. As for the smaller stuff, it tends to fall into the category of shpwing that you and a person come from a similar genetic pool, as in the same region of England or Italy. I have a lot of matches that I juggle here and at FTDNA and Gedmatch since I have colonial New England ancestry on both lines. When I have seen is that I can often match close to 100 people or more at a specific segment, say 1.5cm on a specific chromosome. It may or may not show a true genetic match -- it could just be that we descend from the same region.

That being said, there is value in the smaller segments. See this blog post on it: http://dna-explained.com/2013/10/21/why-are-my-predicted-cou...

Elizabeth