Well what this webpage shows is that some "alien" lifeform is replying to the transmission sent out in 1974. Communicating to us that they have a different DNA structure, that they have big heads and that they communicate via telepathy.
The speaker of the course that we attended feels that these are not aliens but rather demonic/evil forces trying to mislead us into believing that there is such a thing as aliens. In the Bible, these forces are refered to in various places as "gods and goddesses of the air".
Taken in a wider perspective, they are just feeding mankinds' preconceived notions of what aliens are like etc. Notice how people's general perception of aliens are beings with short bodies and big heads and eyes? The aim of all these being to conceal their real identities and to deceive us into thinking they are something else. Kinda like X-files isn't it?
If you go back into the history of different cultures, there are different examples of beings with the ability to fly even before the advent of aircraft. I can't remember the specifics but one example would be the Eyptian "god of the wind and ruler of the air" Amun-Re. These demons adjust their appearances to conform to the myths and culture of the era. Which in our time are flying saucers and aliens. Could there be a kernel of truth in these myths? For what was once history with time becomes legend and legends become myths.
Crop circles are not necessarily "demonic" or "alien" - in fact, most of the crop circles can be attributed to MAN!
www.circlemakers.org documents recent crop circles and have themselves created some crop circles under the cover of darkness.
And there has been some documentaries (Discovery) on the formation of crop circles, and all that you need is some geometric/mathematic knowledge, some rope, some planks and a team of 4-6 people. A crop circle can be created in under 5 hrs.
What does this mean? Well, basically, there are some weird people out there who have nothing better to do than to tie some planks to their feet and go out stomping wheat fields in the middle of the night.
Yes, I have seen the programmes on that too. It's easy to imagine that it's possible to do that with planks and ropes for the conventional circular crop circles. However, even these have been shown to be cover up attempts and the people involved had later admitted to that. The "circles" referred to in the first post are strictly speaking not the conventional circles that can be replicated with the method you described.
Here's a site that explains other factors that cannot be produced by men with planks... Well there are always two sides to everything, read it and see what you think?