Is an anonymous proxy really anonymous?

There are lots of anonymous proxies available on the internet. But can you really trust that an anonymous proxy is going to actually keep you anonymous?  Here's my take on the situation.Open ProxiesThe answer for open proxies, regarding whether they actually keep you anonymous online or not is a big, fat, NO.  Though they're useful because they're convenient, and FREE, the fact of the matter is that you can never be sure who's behind the mask.  Who is running your proxy server? You have no idea. He could be spying on you, or selling your IP data to someone who's paying a handsome price for it. Though there are a lot of honest open proxy admins out there, there is a major risk in using them, so the they get a bad score for anonymity. Plus, you have to worry about the proxy admin being competent enough to set up the proxy right, and you can't always be sure about the level of anonymity of the server (some list it on a gradient scale, some don't list it at all.Premium proxy servicesIf you're paying a fee, then chances are that you level of anonymity is going to be better. At least you can trust that the servers are going to be maintained and up kept properly, and that there's some incentive for the owners to adhere to a privacy policy. After all, they want to have repeat customers, and online based businesses are extremely susceptible to reviews from other customers!But still, the level of anonymity will vary. Some use SSL encryption, and some don't.  Anonymity settings will vary of course.  The advantage here is that there's going to be a support email address where you can actually ask about the level of anonymity.Proxy VS VPNAn anonymous proxy is good for anonymous surfing, but anything outside of your browser is not going to be protect by the proxy server.  If you're running software like VoIP or games, then you're going to need a VPN to hide your IP address.  VPNs, though a completely different type of technology, are often discussed when talking about proxies because they're also used as an anonymous surfing tool.