TL. DR. any coins that don't have any usage (99.9% of the altcoins) shouldn't be counted in total market cap otherwise the total will be a meaningless number. instead consider utilities, how many merchants are using them, etcby now you must have read something about it either on here or reddit or some place else.
yes it is exciting to see the market has grown this much and that number being that big! but what does market cap mean?
it is simply the result of price * supply.
here is an example of why it is such a terrible factor. the following coins (which i chose randomly based on price rise in past 24 hours) has 24.4 billion supply.
now as you can see it is a good example of a dead coin with 3 satoshi value which has been pumped. from 3 satoshi to 82 satoshi and this coin alone has contributed to 50 million dollars increase in market cap
http://i.imgur.com/v3NFWxb.jpgare you still saying market cap is a good factor?
take a look at more coins if you don't agree with the above screen shot and want to argue that coin is good , blah blah...
the following coins are all dead coins. mostly in the range of 1 satoshi and even less. some of them don't even have a bitcoin market anymore. they are being traded with smaller coins such as Doge at funny prices such as 0.01 Doge per coin!
all the coins that i have circled have gone up from <1 satoshi up to prices you see. each in >500% (the circled percentage are only 24 hour rises).
look at the comical market caps:
http://i.imgur.com/AFRzDlX.jpghintto see these coins you have to scroll all the way down to the bottom of the coinmarketcap.com page and then click next 100 a couple of times to reach these coins
Thank you for this and it is clear to me now. I do have a question though. What with there being so many newcomers to cryptocurrency wouldn't the psychological effect of a coin having a higher price per piece have a significant effect, exactly because people look at the price and not the market value? I know that's why I invested a lot in XRP ripple and hope to someday have 1 BTC