Does anyone use a phone forwarding service (like this)?

I found several free ones available like the above but am wondering if there are any downsides.

I just noticed the one above is maximum 1 week. I'm looking for a permanent one.

Are you talking about something similar to Jaxtr

Yeah, thanks. That looks pretty sweet. I'm going to try it out.

I see now that Jaxtr is not what I'm looking for. I'm looking for a "phone number" that I can use for websites etc. that require a phone number, but where I don't want to reveal my cell or land line phone number.

Like this, but permanent rather than temporary.

This is free, http://inumbr.com/
Initially you can set it up to expire after a max of 1 week, but just log in every week to extend the "life" of your free number.

Actually I just checked, they have an additional feature to extend the expiration date of your virtual number.