How protected are you with proxies?

I set up my FF useing apekillas method he posted. Grabbed a proxy from one of the lists in the sticky.
I went to ipchicken.c0m and sure enough, it showed the proxy but when i went to whatismyip.c0m it showed my real ip and had a big red warning about a suspected proxy server being used.
So I'm wondering if sites i intend on using this method with can see through the proxy or if they can tell if you're using one.
I did clear all cache and cookies btw.

i dont think public proxy sites are all that safe .i think a proxy software would work better

Which site did you try? The one I use seems to work pretty well and has many different sites which you can pick to use that can hide your ip. I tried the sites you mentioned and everything worked like it was supposed to. Check it out:

you have to be very careful in selection of proxy. bcos most ip's of large proxy sites on net are identified and put in blacklist.

the reason it showed your real ip because your using
tranparent proxy use anonymous or socks5 or 4

The best solution to get anonymity is to use a VPN imo, most proxies are sucks based on my experience, use StrongVPN their service is amazing but a bit costly and gives you only one ip, if you need to change your ip most frequent I'd recommend to test Hide My IP 2008 the service is pretty amazing and you can test a free 3 days trail after then if you liked how the program working my advice to you is to go with the Premium Service it costs more money but gives you faster IPs from more countries and deserves each penny
Stickign with free is sucks belive me, invest some bucks in your right tobe anonymous!