1) cmc shows me a market cap for $432M and a trade volume for $12M when I check Eth.
2) wci shows me a market cap for $433M and a trade volume for $12M when I check Eth.
What is the difference between those sites? Their default ranking system.
CMC ranks by the total market cap (duh, that's the name), WCI ranks by 24h trade volume.
And that kids is the reason why Eth is ranked #2 on cmc and #3 on wci.
And the reason why the trade volume on CMC for LTC is that low seems to be the fact, that they don't list/crawl the chinese exchange Huobi (which has 92% of the volume isted on WCI).
This explain it all I thought coinmarketcap is the only source but since you have given us this fact I am going to bookmark this site and made comparison,I didn't know that coinmarketcap is leaving china based exchanges,they are a very strong exchanges ..