It is safe and does provide a lot of heat and moisture to the house in the winter. (If you have a gas dryer, check with your gas provider, I have electric and it's safe for that.) Check the link to a nice, inexpensive little vent that catches the lint much better than just a nylon stocking would. You put a little water into the cup and it catches the lint, you empty it every few loads and you get no lint all over the place.
In the summer, you'd have to re hook the vent to an outside vent or open some windows in your laundry room as it does get too much moisture and heat then.