The act of doing so, by your conscious will, will be the same as if you actually lit a candle in your home, which at times may not be the safest way to go.
Candles burn down, the virtual candle lives on forever.
Be sure your purpose is ethical and you have permission of anyone else who may be involved in the lighting of this candle. When you light your candle and enter a message it will go on the permanent web page for others to see. Your prayer, spell, whatever you want to call it, will exist forever.