Kongregate is one of the biggest web game portals in the world. Originally a site for flash games they've been accepting HTML5 games for a while. Kongregate shares up to 50% of their advertising revenue with the game developer so they are a good place to start making money from your games.
How to publish to Kongregate
1. Download a zip file version of your game. Follow the self-hosting instructions.
2. Unzip the contents of your exported zip file and you will see a folder containing all your files.
3. Create a new zip file which does not include the containing folder.
Select all the files in your unzipped folder, right click and select Send to -> Compressed (zipped) folder (More info)
Select all the files in your unzipped folder, right click (or Ctrl-Click) and select "Compress X Items"
4. Visit the Upload your game page on Kongregate.
5. Fill in all the details on the upload form as required. Set the index.html file to the file found in your game's export folder and select "I would like to upload additional files" and add the new zip file you created in step 3.
6. Test your game and publish!