VeloViewer and Strava; what does it all mean?

Yesterday I used Strava for the first time. I rode a 63km route topping out on the Brickworks climb Pott Shrigley. I now find I am *competing* with Simon Yates! who is the KoM on said climb. He is only about 2.5 to 3 times quicker than me so not much chance of beating him. I find myself over 3000th place, which is slow. Going uphill is not my forte, I am more of a ranger used to the flat plains of Mancheshire, like the Volvo estate of riders, alright once up to speed, not very aero. But I need to do these things to complete the events I want to do.
This is the fourth time I have done that climb this summer and third in the last two weeks. It is getting easier but not faster. As well as showing me how much faster others are doing it shows me straight away the amount of climbing gain I have done, 619m yesterday. That is the number one feature I think as it would often take ages working this out later on mapping sites like MapmyRide which are frustrating to plot out the same course in retrospect.

That's the good, but looking at my route shows all the other segments. There were 73 in total including some bewilderingly fast descents and sprints. Last week I checked Strava for the shortened London 100 route to see if I could get the reduced gain figure from that (answer, yes I could) and the guy's track I found showed over 300 segments on it, up to 19 overlapping segments at a time. Just what does all of it mean? Are segments only created for people's own vanity so they can set a KoM that no one else is aware of? Yesterday I was 24th on a segment without knowing it was there, so I ranged from the bottom 1% to top 85% or percentile. I can see the point of a segment on a known climb like the Brickworks but most of the segments are just a few hundred metres long. Competing to get these KoM's just seems like a distraction from a good ride. I am chuffed if I can manage to sustain 30kph over 50+km, I don't think this style of riding is going to get me many podiums unless I mark my own routes as segment (which is cheating right, because no one else will bother to do that route?)

Apart from my Strava cherry I also signed up for Veloviewer thingy which looks like some teeth from the Bumper Book of British Smiles. I know I have to do some more rides to fill in the gaps but what does the graphs represent? What will it tell me when it starts to tell me something?

Taking off the Strava L plates and putting on the P plate.