I recently added data from a .csv file into a Web Map. Here are a few things I learned from talking to ESRI Support.
1. When you Add Layer from File in a Web Map, it creates a "Feature Collection." This is different from a Feature Service. (If I understand it correctly, the features are temporary until you choose "Save Layer" from the dropdown in the web map, then it creates the Feature Collection.) 2. The Feature Collection will show up in My Content and appear the same as a Feature Service would. The icon is exactly the same and the item even says "Features" under Type. 3. The Feature Collection will not show up under "My Hosted Services" in ArcMap. 4. In order to create a Feature Service, you have to go to My Content > Add Item > Add the .csv file > Check the "publish a feature service" checkbox and create a hosted feature service from it. 5. This is confusing and misleading.
Why wouldn't adding a .csv to a Web Map publish it as a Feature Service? Why would you have to leave your map and go to My Content to perform the same task that could be performed much quicker in the Web Map? It seems to me that this process could be improved.