Python functions to determine if a given ticker symbol is an ETF
Any time you're dealing with structured data, use a proper parser for it. 

url = 'http://finance.yahoo.com/d/quotes.csv?s=%s&amp;f=%s' % (symbol, tag)


In this case, you want urllib.parse.

Please use a context manager for:

request = Request(url)
response = urlopen(request)


eg.

with urlopen(Request(url)) as response:
    ...


Context managers are good. It's a shame they're so under-used. On older Pythons, you should use contextlib.closing instead.

I would generally merge these lines into a long return:

content = response.read().decode().strip().strip('"')
return content


Consider that in

ticker = ticker.upper()
return True if get_name(ticker) != 'N/A' else False


True if some_bool else False is just some_bool, so write

return get_name(ticker.upper()) != 'N/A'


instead.