Expense Ratios represent the amount of money a fund spends on management.
The new ETFs have relatively low expense ratios compared with traditional mutual funds, which is one feature that makes them so attractive.
Advertising costs are NOT included in the Expense Ration of a fund. You should also check for load and any additional administrative fees or advisory costs.
Most online trading portals have information on market jargons like this. Check out Reliance , HDFC and ICICI online websites.