iframe. Doesn't sound like an evil word does it? But if you use them in posts here, under certain circumstances you are in fact engaging in a criminal activity. ie; bandwidth theft! It's also against copyright issues.
I know, I'm being a copyright nazi. But this is a big one! Especially since the sites it's scamming from are often small personally created sites that can barely afford the bandwidth they use. Stealing from the mouths of babes and beggars you are! ok, not quite, but still. Should be avoided at all costs.
How you may be thieving bandwidth: When you post in AW, and wish to show some neat site you found, and stick it's url in an <iframe>, you are essentially capturing that page inside that post. Every time someone reads that post and accesses your cute little iframe, they are causing that iframed page to load. That takes bandwidth. It is NOT using AW bandwidth! It's using the site stuck in that little iframe jail.
If you wish to iframe a site that you have authorization to do such a thing, that's one thing. If they are ok with it and say so in writing, well, ok for you. If not, you are stealing some very expensive bandwidth. expensive as hell in fact! Just shelled over a hundred dollars for extra bandwidth in my own site. ouch! So don't do it please. Also, if you do have permission, and use iframe in a post, please include a link to the site itself also? I mean, alot of folks have iframe turned off in net options as it is a vulnerability for viruses. (it is, but longer story) so they cannot see your nifty iframed site, and cannot access it either on their own.